Annals of the American Thoracic Society

Rationale: Interstitial lung disease (ILD) develops in a large percentage of patients with connective tissue disease (CTD) and is associated with increased morbidity and mortality. Patients with CTD-associated ILD (CTD-ILD) often present at a young age, suggesting that ILD likely impacts workplace productivity.

Objectives: We aimed to determine the employment rate and workplace productivity loss, along with its associated factors and estimated costs, in patients with fibrotic CTD-ILD.

Methods: Patients with fibrotic CTD-ILD from the six centers of the Canadian Registry for Pulmonary Fibrosis were eligible. Health-related productivity loss was assessed using the Work Productivity and Activity Impairment questionnaire. Proposed factors associated with low workplace productivity were forced into a multivariable regression model. Average productivity loss in hours/week was used to calculate the costs of productivity loss based on hourly wages obtained from national census data matched for age and sex. Workplace productivity loss outcomes were compared between patients with CTD-ILD and patients with a non-CTD fibrotic ILD.

Results: Of 375 eligible patients with fibrotic CTD-ILD, 113 (30%) were employed. Productivity loss was reported by 59% of employed patients, with a mean loss of 9.4 ± 1.2 hours/week, including 3.9 ± 0.9 hours/week from absenteeism and 5.5 ± 0.7 hours/week from presenteeism. Employment among patients 25–54 years of age with fibrotic CTD-ILD was 27% lower than that in the matched general Canadian population (56% vs. 83%; P < 0.001). Employment among patients ≥55 years of age with CTD-ILD was 17% lower than that in the matched population (19% vs. 36%; P < 0.001). Workplace productivity loss was not associated with respiratory symptoms or lung physiology. Annual costs of productivity loss were calculated at 13,593 Canadian dollars per employee with fibrotic CTD-ILD. Workplace productivity loss was similar in patients with fibrotic CTD-ILD and those with non-CTD fibrotic ILD.

Conclusions: Patients with fibrotic CTD-ILD frequently report workplace productivity loss, which is unexplained by respiratory symptoms or lung physiology and is associated with significant costs.

Connective tissue diseases (CTDs) include several systemic disorders that typically occur at a young age and result in pulmonary involvement. Interstitial lung disease (ILD) is a heterogeneous group of disorders that are characterized by inflammation and/or fibrosis of the interstitium (1). ILD is a frequent complication of CTD and is associated with significant morbidity and mortality (2). Fibrotic CTD-ILD often presents with dyspnea and cough, which reduce quality of life (3, 4). Dyspnea, the most frequent symptom of ILD, is independently associated with physical function in patients with CTD-associated ILD (5).

The disabling symptoms of fibrotic CTD-ILD suggest that ILD likely impacts workplace productivity in patients with this disorder, who are frequently of working age; however, no studies have evaluated this possibility. Therefore, our objectives were to determine the employment rate and workplace productivity loss among individuals with fibrotic CTD-ILD, identify variables associated with productivity loss, estimate its total societal costs, and compare the outcomes with those of patients with non-CTD fibrotic ILD. We hypothesized that workplace productivity loss would be associated with dyspnea and cough after adjusting for physiologic disease severity, age, sex, and smoking pack-years, similar to what was previously demonstrated in patients with non-CTD fibrotic ILD (6). Because patients with CTD-ILD are typically younger than those with non-CTD fibrotic ILD and also have additional features related to the multisystem involvement of CTD-ILD, we also hypothesized that workplace productivity loss would be higher in individuals with fibrotic CTD-ILD than in those with non-CTD fibrotic ILD.

Study Overview

Patients were identified and data were extracted from the Canadian Registry for Pulmonary Fibrosis (CARE-PF), which is a six-center prospective registry (7). All eligible patients who were enrolled from January 1, 2015 to July 01, 2017 were included, and measurements were obtained from both incident and prevalent patients at the time of enrollment. The eligibility criteria for this substudy included a diagnosis of fibrotic CTD-ILD, verified by a rheumatologist and according to established diagnostic criteria when available, but excluding patients with interstitial pneumonia with autoimmune features (8). Patients with other non-CTD subtypes of fibrotic ILD were used as disease control subjects. The research ethics boards of all participating centers approved this substudy.

Workplace Productivity

Patient-completed Work Productivity and Activity Impairment (WPAI) questionnaires were used to determine health-related workplace productivity loss (9). The WPAI was designed for patients with chronic medical conditions and has since been validated in multiple chronic diseases, including asthma (10) and rheumatoid arthritis (11). The questionnaire has six questions that document lost work time due to absenteeism (inability to work secondary to health issues) and presenteeism (impaired work functionality despite physical presence), with a 1-week recall period. Patients are asked to indicate the number of work hours that were missed in the last week due to health-related issues (absenteeism), and to provide an estimate of how much workplace productivity was affected by their health (presenteeism). Weekly hours lost owing to presenteeism were calculated as the total hours worked per week multiplied by the fraction of limitation. The total weekly hours lost secondary to health problems were calculated for each employed patient as the sum of hours lost from absenteeism and presenteeism.

The primary analysis assumed that all employed patients with missing absenteeism and/or presenteeism data (4% of the cohort) had no absenteeism and/or presenteeism. This provided the lowest (most conservative) estimate for workplace productivity loss and its associated costs. A sensitivity analysis excluded employed patients with missing data. Records of unemployed patients <70 years old from the largest CARE-PF center (one-third of the study population) were screened to determine the number of patients who were unable to work secondary to disabilities that were attributed to CTD-ILD.

Additional Study Measurements

Demographics, smoking history, supplemental oxygen use, dyspnea score, cough severity, and lung function were recorded. Dyspnea was assessed using the University of California, San Diego Shortness of Breath Questionnaire, a patient-reported questionnaire that assesses dyspnea associated with 21 common daily activities and three additional questions about the impact of dyspnea (12). Each question has scores ranging from 0 (“not at all”) to 5 (“maximal”), producing a total score of 0–120. Cough was measured using a patient-reported 100-mm visual analog scale (VAS), ranging from “no cough” to “worst cough severity imaginable” (13). The cough VAS is a simple, rapid measurement of cough severity that has been used effectively in studies of patients with fibrotic ILD (14). Forced vital capacity (FVC) and diffusing capacity of the lung for carbon monoxide (DlCO) were measured as percent predicted values according to standard recommendations (15, 16).

Statistical Analysis

The patients’ baseline characteristics are provided as mean ± standard deviation or median (interquartile range). Data are reported for the full cohort and in patients older or younger than 70 years (this threshold was used considering the increasing frequency of employment for Canadian men and women 65–69 years old (17). A secondary analysis was based on a threshold of 65 years. Data from our cohort were compared with the expected employment rate in a general Canadian population (18), accounting for the age and sex distribution of our study population.

The association of baseline features with workplace productivity loss was examined using a Spearman correlation for continuous variables and a Wilcoxon rank-sum test for categorical variables. Multivariable analysis used a zero-inflated negative binomial regression, which includes both a logistic regression model for the probability of individuals reporting no productivity loss, and a negative binomial model for the amount of workplace productivity loss in those who reported productivity loss. Prespecified variables forced into the model included age, sex, smoking pack-years, FVC, DlCO, dyspnea score, and cough severity. Productivity loss was compared for male and female patients and for scleroderma, rheumatoid arthritis, and inflammatory myopathies using a Wilcoxon rank-sum test or Kruskal-Wallis test for continuous variables and Chi-square test for categorical variables.

Costs of productivity loss were calculated using the mean hours of work lost multiplied by age- and sex-matched average national hourly wages (19). Average annual costs of workplace productivity loss in the full cohort were calculated by adding costs of productivity loss in employed patients to costs of disability in patients on full-time disability, assuming no productivity loss in the remaining unemployed patients not on disability. Annual costs of productivity loss were also determined for patients <50 and ≥50 years old. All costs are reported in 2017 Canadian dollars (CAD).

Workplace productivity loss outcomes among patients with fibrotic CTD-ILD were compared with those observed in 650 patients with non-CTD fibrotic ILD who have been previously reported, including 380 who were ≤70 years old (6). This was done using a logistic regression for employment rate and proportion of employed patients with productivity loss, and a zero-inflated negative binomial regression for levels of productivity loss (h/wk) and their associated costs, adjusting each model for age, sex, and ILD severity (FVC and DlCO). A two-tailed P value of <0.05 was considered statistically significant. Analyses were performed with R statistical software, version 3.4.3 (R Foundation for Statistical Computing).

Baseline Characteristics

Of 1,285 patients with ILD, 375 patients with fibrotic CTD-ILD were eligible, including 305 (81%) who were ≤70 years old and 244 (65%) who were ≤65 years old (Table 1 and Figure 1). The most frequent diagnoses were systemic sclerosis (32.5%) and rheumatoid arthritis (21%). The average age was 60 ± 12 years, most patients were female, and half were former smokers. There was a mild and moderate reduction in FVC and DlCO, respectively. Two-thirds of the patients were on ILD therapy at enrollment. Patients who were employed (30%) were younger, were less likely to be ever-smokers and reported less smoking pack-years, had higher DlCO, and were more likely to currently be on therapy than patients who were unemployed.

Table 1. Baseline characteristics

VariableAll Patients (N = 375)Employed (n = 113)Unemployed (n = 262)
Age, yr60 ± 1253 ± 1164 ± 11
Male sex115 (31%)42 (37%)73 (28%)
Ever-smoker199 (53%)50 (44%)149 (57%)
Pack-years smoking0.4 (0–15)0 (0–4)2.3 (0–21)
Supplemental oxygen use57 (15%)5 (0.04%)52 (20%)
Time since diagnosis, yr2.9 (0.9–5.8)3.1 (0.9–6.0)2.7 (1.0–5.7)
FVC% predicted75 ± 2076 ± 1875 ± 21
DlCO% predicted57 ± 1960 ± 1856 ± 19
ILD pharmacotherapy246 (66%)82 (73%)164 (63%)
 Corticosteroid162 (43%)52 (46%)110 (42%)
 Azathioprine43 (11%)14 (12%)29 (11%)
 Mycophenolate mofetil149 (39%)51 (45%)98 (37%)
 Cyclophosphamide4 (1%)0 (0%)4 (2%)
 Rituximab24 (6%)8 (7%)16 (6%)
 Scleroderma122 (32.5%)35 (31%)87 (33%)
 Rheumatoid arthritis78 (21%)20 (18%)58 (22%)
 Inflammatory myopathies68 (18%)23 (20%)45 (17%)
 Mixed CTD34 (9%)13 (12%)21 (8%)
 Undifferentiated CTD30 (8%)7 (6%)23 (9%)
 Sjogren’s syndrome26 (7%)6 (5%)20 (7%)
 SLE14 (3.7%)7 (6%)7 (3%)
 Others3 (0.8)2 (2%)1 (1%)

Definition of abbreviations: CTD = connective tissue disease; DlCO = diffusing capacity of the lung for carbon monoxide; FVC = forced vital capacity; ILD = interstitial lung disease; SLE = systemic lupus erythematosus.

Data are presented as mean ± standard deviation, n (%) or median (interquartile range).

Employment and Workplace Productivity Loss

Of the 375 patients with fibrotic CTD-ILD, 113 (30%) were employed. Of the 305 patients ≤70 years of age and the 244 patients ≤65 years of age, 108 (35%) and 105 (43%) were employed, respectively. Employment among patients with fibrotic CTD-ILD between 25 and 54 years of age was 27% lower than age- and sex-matched rates reported in the general Canadian population (56% vs. 83%; P < 0.001; Figure 2). Employment among patients with CTD-ILD who were ≥55 years of age was 17% lower than matched control subjects (19% vs. 36%; P < 0.001; Figure 2). In a subgroup analysis of patients enrolled at the largest CARE-PF center, ILD and/or CTD were documented as the reason for long-term or permanent disability in 14 of 60 (23%) unemployed patients ≤70 years old, and 13 of 44 unemployed patients ≤65 years old (30%).

Workplace productivity loss was reported by 59% of the 113 employed patients, including absenteeism that affected 24% and presenteeism that affected 51% (Table 2). Among employed patients, average productivity loss was 9.4 ± 1.2 hours/week, with 3.9 ± 0.9 hours/week from absenteeism and 5.5 ± 0.7 hours/week from presenteeism. Findings were similar when employed patients with missing data were excluded (Table E1 in the online supplement). Results were similar for men and women, across CTD-ILD subtypes (Figure 3), and for patients on or not on CTD-ILD therapy (9.1 ± 1.4 vs. 9.9 ± 2.3 h/wk; P = 0.69).

Table 2. Workplace productivity loss for employed patients stratified by sex and subtype of connective tissue disease–associated interstitial lung disease

Productivity Loss OutcomeAll (N = 113)Male (n = 42)Female (n = 71)SSc (n = 35)RA (n = 20)IM (n = 23)
Total hours worked29.8 ± 1.731.6 ± 3.028.7 ± 1.931.0 ± 2.129.2 ± 5.132.1 ± 3.9
Percent with productivity loss
 Any type59%69%54%71%60%48%
Hours lost
 Any type9.4 ± 1.211.5 ± 2.18.1 ± 1.510.9 ± 2.210.4 ± 2.810.8 ± 3.1
 Absenteeism3.9 ± 0.95.3 ± 1.73.0 ± 1.04.1 ± 1.73.2 ± 1.95.9 ± 2.7
 Presenteeism5.5 ± 0.76.2 ± 1.35.1 ± 0.96.8 ± 1.47.2 ± 1.94.9 ± 2.0
Estimated annual costs of workplace productivity loss, mean*
 Any type$13,593$18,158$10,892$15,793$14,945$16,583

Definition of abbreviations: IM = inflammatory myopathies; RA = rheumatoid arthritis; SSc = systemic sclerosis.

*Costs are reported in 2017 Canadian dollars.

Features Associated with Low Workplace Productivity

Workplace productivity loss was associated with increased smoking pack-years, worse cough, and worse dyspnea on unadjusted analysis (Table 3). On adjusted analysis, the odds of reporting workplace productivity loss and the incidence rate (h/wk) of workplace productivity loss were not associated with either dyspnea or cough (Table 4).

Table 3. Variables associated with workplace productivity loss (h/wk) on unadjusted analysis

VariableCorrelation CoefficientP Value
Age, yr−0.15 (−0.34 to 0.04)0.11
Pack-years smoking0.33 (0.13 to 0.49)<0.001
FVC% predicted−0.13 (−0.32 to 0.06)0.17
DlCO% predicted−0.17 (−0.34 to 0.025)0.08
Cough VAS0.23 (0.03 to 0.41)0.02
Dyspnea score (UCSD SOBQ)0.29 (0.10 to 0.46)0.002

Definition of abbreviations: DlCO = diffusing capacity of the lung for carbon monoxide; FVC = forced vital capacity; UCSD SOBQ = University of California, San Diego Shortness of Breath Questionnaire; VAS = visual analog scale.

Table 4. Variables associated with workplace productivity loss on adjusted analysis

Zero-Inflation ModelOR (95% CI)P Value
Age, yr1.04 (0.99–1.09)0.11
Male0.42 (0.14–1.21)0.11
Pack-years smoking0.95 (0.90–1.00)0.09
FVC% predicted0.98 (0.95–1.01)0.32
DlCO% predicted1.02 (0.98–1.04)0.37
Cough severity (VAS)0.98 (0.96–1.00)0.22
Dyspnea score (UCSD SOBQ)0.97 (0.94–1.00)0.06
Count ModelIRR (95% CI)P Value
Age, yr0.98 (0.95–0.99)0.029
Male1.38 (0.79–2.40)0.25
Pack-years smoking1.01 (0.99–1.02)0.21
FVC% predicted1.00 (0.98–1.02)0.60
DlCO% predicted1.00 (0.99–1.01)0.81
Cough severity (VAS)1.01 (0.99–1.02)0.23
Dyspnea score (UCSD SOBQ)1.00 (0.99–1.01)0.35

Definition of abbreviations: CI = confidence interval; DlCO = diffusing capacity of the lung for carbon monoxide; FVC = forced vital capacity; IRR = incidence rate ratio; OR = odds ratio; UCSD SOBQ = University of California, San Diego Shortness of Breath Questionnaire; VAS = visual analog scale.

The zero-inflation model estimates the probability of reporting no workplace productivity loss. The count model estimates the incidence rate of workplace productivity loss in those reporting productivity loss.

Costs of Workplace Productivity Loss

The annual cost of workplace productivity loss was $13,593 CAD per patient with CTD-ILD among those who were employed (Table 2). Of this amount, $5,717 CAD was secondary to absenteeism and $7,876 CAD was secondary to presenteeism. The costs of productivity loss were $18,158 and $10,892 CAD among employed male and female patients, respectively (P = 0.06), and were similar across systemic sclerosis, rheumatoid arthritis, and inflammatory myopathies ($15,793, $14,945, and $16,583 CAD, respectively; P = 0.19). The annual costs of workplace productivity loss were $19,479 CAD in employed patients <50 years of age and $10,243 CAD in patients ≥50 years of age. Annual costs of workplace productivity loss were $5,640 CAD per patient when averaged across the entire fibrotic CTD-ILD cohort.

Workplace Productivity Loss in Fibrotic CTD-ILD Compared with Non-CTD Fibrotic ILD

After adjustment for age, sex, FVC, and DlCO, the employment rate was similar between patients with CTD-ILD and those with non-CTD fibrotic ILD who were ≤70 years of age (35% vs. 32%; odds ratio [OR], 1.37 [95% confidence interval [CI], 0.91–2.09]; P = 0.13; Figure 4). The proportion of employed patients reporting productivity loss of any type was similar between CTD-ILD and non-CTD fibrotic ILD (59% vs. 55%), including after adjustment for age, sex, and ILD severity (OR, 0.90 [95% CI, 0.49–1.65]; P = 0.74; Figure 4), with similar levels of productivity loss (9.4 ± 1.2 vs. 7.8 ± 0.9 h/wk; P = 0.59) and similar associated costs ($13,593 vs. $11,610 CAD; P = 0.89). Patients with fibrotic CTD-ILD had more frequent absenteeism and associated costs than those with non-CTD fibrotic ILD. In a similarly adjusted analysis, productivity loss was comparable between fibrotic CTD-ILD and non–idiopathic pulmonary fibrosis (IPF) fibrotic ILD (9.4 ± 1.2 vs. 7.9 ± 1.5 h/wk; P = 0.88) and between fibrotic CTD-ILD and IPF (9.4 ± 1.2 vs. 7.7 ± 1.0 h/wk; P = 0.43).

This large prospective cohort study is the first to show that the majority of patients with fibrotic CTD-ILD are potential participants in the workforce, that only 35% of patients <70 years of age are currently employed, and that workplace productivity loss in this cohort is significantly greater than that in a matched Canadian population. This workplace productivity loss is associated with significant costs, further illustrating the overall burden of CTD-ILD.

The unemployment rate in our CTD-ILD cohort (57% in those ≤65 years of age) is higher than those previously reported for patients with CTD who did not have an ILD, such as systemic sclerosis (37%) (20), systemic lupus erythematosus (38%) (21), inflammatory myopathies (25%) (22), and rheumatoid arthritis (25%) (23). Among employed patients, productivity loss in our cohort of patients with CTD-ILD (absenteeism in 24% and presenteeism in 51%) was similar to that reported in a 2017 study of 476 patients with systemic sclerosis enrolled in the Australian Scleroderma Cohort Study (absenteeism in 16 and presenteeism in 63%) (24). Collectively, these findings demonstrate the important impact of CTD-ILD on workplace productivity.

The decreased workplace productivity reported in our population represents a significant financial burden, estimated at $13,593 CAD per employee annually. This translates into $10,467 U.S. dollars, £8,130 British pounds, and €9,310 Euros per employee using 2017 conversion rates. The total annual cost averaged across the entire CTD-ILD population was $5,640 CAD per employee, with this value allowing calculation of the total burden of productivity loss given a population prevalence of CTD-ILD. This translates into $4,342 U.S. dollars, £3,373 British pounds, and €3,862 Euros. These costs associated with workplace productivity loss in our cohort should be added to direct healthcare costs (e.g., costs of physician visits, investigations, medications, and hospital admissions) for estimating the total costs attributable to fibrotic CTD-ILD.

In contrast to previous findings in patients with non-CTD fibrotic ILDs (6), we found that workplace productivity loss in patients with CTD-ILD was not associated with respiratory symptoms or physiologic severity. Previous studies in patients with CTD who did not have an ILD have suggested the potential importance of older age (25, 26), greater disease activity (2527), fatigue (25, 26), worse health status (25, 26, 28), lower education level (25, 28), longer disease duration (29, 30), higher global disability (28, 29, 31), and lower health-related quality of life (24). Disease-specific factors, such as the presence of radiographic erosions in patients with rheumatoid arthritis (30) and severity of ILD in patients with systemic sclerosis (24, 27), are less frequently identified as significant determinants of workplace productivity loss. These multiple contributing factors highlight the importance of screening for workplace productivity loss in all patients with CTD-ILD of working age, even if the ILD component is not advanced.

Intervention programs aiming to improve workplace productivity in patients with CTD have recently been evaluated. In 2017, an economic evaluation of a randomized controlled trial showed no benefit and higher costs from a targeted participatory workplace intervention in employed patients with rheumatoid arthritis who were experiencing minor difficulties in work functioning (32). Several studies in patients with a variety of CTDs have suggested that workplace productivity can be preserved by early pharmacological intervention and disease remission (25, 3335). Together, these findings suggest that early therapy may be the best approach to limit productivity loss in working-age patients with fibrotic CTD-ILD. The association of cigarette smoking with workplace productivity loss in the unadjusted analysis in our study suggests that strategies aimed at smoking cessation may also reduce workplace productivity loss.

Our study has some limitations. Our study population is derived from several Canadian centers that receive referrals from large urban and rural regions, and our findings may not be fully generalizable to populations with different demographics, retirement ages, or other incentives to work. We did not obtain a detailed employment history for patients (e.g., via the Valuation of Lost Productivity questionnaire) (36), and thus did not calculate patient-specific hourly wages for our cohort. We instead chose to contextualize our employment and income data in comparison with national population-based data, which is likely a more generalizable and valuable approach. We also did not enroll people without ILD, and instead compared outcomes with those reported in previous studies of patients with CTD and in our cohort of patients with non-CTD fibrotic ILD, and with Canadian population–based data. We did not adjust for comorbidities, given the narrow distribution of the Charlson Comorbidities Index across our cohort (37), which suggests that this index has a limited ability to quantify the extent and severity of comorbidities in patients with ILD, including some relevant ILD comorbidities such as gastroesophageal reflux and sleep-disordered breathing. Finally, some patients may prefer part-time employment or consider full-time employment somewhat optional, and patients’ choices to reduce their work hours for reasons unrelated to health issues may not be captured by the WPAI. However, this possibility should have a similar effect on both patients with fibrotic CTD-ILD and those with non-CTD fibrotic ILD, as well as matched control subjects from the general Canadian population.

In summary, this study of large prospective cohort of patients with fibrotic CTD-ILD shows that workplace productivity loss is reported in 59% of employed patients, with a considerable percentage of additional patients on chronic disability secondary to their CTD-ILD. It also shows that workplace productivity loss is associated with significant costs and is unexplained by respiratory symptoms, suggesting that other unmeasured CTD-related factors might be important contributors to productivity loss. These findings further illustrate the substantial burden of fibrotic CTD-ILD on both individual patients and society as a whole. Further studies are needed to identify major factors that contribute to productivity loss, and to suggest potential intervention strategies for patients with fibrotic CTD-ILD.

The authors thank the patients who agreed to participate in CARE-PF.

1 . Schwarz MI, King TE. Interstitial lung disease. Raleigh, NC: PMPH USA; 2003.
2 . Assayag D, Ryerson CJ. Determining respiratory impairment in connective tissue disease-associated interstitial lung disease. Rheum Dis Clin North Am 2015;41:213223.
3 . Demoruelle MK, Mittoo S, Solomon JJ. Connective tissue disease-related interstitial lung disease. Best Pract Res Clin Rheumatol 2016;30:3952.
4 . Palm O, Garen T, Berge Enger T, Jensen JL, Lund M-B, Aaløkken TM, et al. Clinical pulmonary involvement in primary Sjogren’s syndrome: prevalence, quality of life and mortality: a retrospective study based on registry data. Rheumatology (Oxford) 2013;52:173179.
5 . Swigris JJ, Yorke J, Sprunger DB, Swearingen C, Pincus T, du Bois RM, et al. Assessing dyspnea and its impact on patients with connective tissue disease-related interstitial lung disease. Respir Med 2010;104:13501355.
6 . Algamdi M, Sadatsafavi M, Fisher JH, Morisset J, Johannson KA, Fell CD, et al. Costs of workplace productivity loss in patients with fibrotic interstitial lung disease. Chest 2019;156:887895.
7 . Ryerson CJ, Tan B, Fell CD, Manganas H, Shapera S, Mittoo S, et al. The Canadian registry for pulmonary fibrosis: design and rationale of a national pulmonary fibrosis registry. Can Respir J 2016;2016:3562923.
8 . Fischer A, Antoniou KM, Brown KK, Cadranel J, Corte TJ, du Bois RM, et al.; “ERS/ATS Task Force on Undifferentiated Forms of CTD-ILD”. An official European Respiratory Society/American Thoracic Society research statement: interstitial pneumonia with autoimmune features. Eur Respir J 2015;46:976987.
9 . Reilly MC, Zbrozek AS, Dukes EM. The validity and reproducibility of a work productivity and activity impairment instrument. Pharmacoeconomics 1993;4:353365.
10 . Andreasson E, Svensson K, Berggren F. PRP11 the validity of the work productivity and activity impairment questionnaire for patients with asthma (WPAIASTHMA): results from a web-based study. Value Health 2003;6:780.
11 . Zhang W, Bansback N, Boonen A, Young A, Singh A, Anis AH. Validity of the work productivity and activity impairment questionnaire: general health version in patients with rheumatoid arthritis. Arthritis Res Ther 2010;12:R177.
12 . Swigris JJ, Han M, Vij R, Noth I, Eisenstein EL, Anstrom KJ, et al. The UCSD shortness of breath questionnaire has longitudinal construct validity in idiopathic pulmonary fibrosis. Respir Med 2012;106:14471455.
13 . Spinou A, Birring SS. An update on measurement and monitoring of cough: what are the important study endpoints? J Thorac Dis 2014;6:S728S734.
14 . Horton MR, Santopietro V, Mathew L, Horton KM, Polito AJ, Liu MC, et al. Thalidomide for the treatment of cough in idiopathic pulmonary fibrosis: a randomized trial. Ann Intern Med 2012;157:398406.
15 . Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, et al.; ATS/ERS Task Force. Standardisation of spirometry. Eur Respir J 2005;26:319338.
16 . Macintyre N, Crapo RO, Viegi G, Johnson DC, van der Grinten CPM, Brusasco V, et al. Standardisation of the single-breath determination of carbon monoxide uptake in the lung. Eur Respir J 2005;26:720735.
17 . Carrière Y, Galarneau D. Delayed retirement: a new trend? Perspect Labour Income 2011;12:116.
18 . Statistics Canada. Table 14-10-0287-01. Labour force characteristics, monthly, seasonally adjusted and trend-cycle, last 5 months. 2020 [accessed 2017 Nov 8]. Available from:
19 . Statistics Canada. Table 14-10-0065-01. Employee wages by job permanency and union coverage, monthly, unadjusted for seasonality. 2020 [accessed 2017 Nov 8]. Available from:
20 . Decuman S, Smith V, Verhaeghe ST, Van Hecke A, De Keyser F. Work participation in patients with systemic sclerosis: a systematic review. Clin Exp Rheumatol 2014;32(Suppl 86):S-206-13.
21 . Ekblom-Kullberg S, Kautiainen H, Alha P, Leirisalo-Repo M, Julkunen H. Education, employment, absenteeism, and work disability in women with systemic lupus erythematosus. Scand J Rheumatol 2015;44:157162.
22 . Regardt M, Welin Henriksson E, Sandqvist J, Lundberg IE, Schult M-L. Work ability in patients with polymyositis and dermatomyositis: an explorative and descriptive study. Work 2015;53:265277.
23 . Kessler RC, Maclean JR, Petukhova M, Sarawate CA, Short L, Li TT, et al. The effects of rheumatoid arthritis on labor force participation, work performance, and healthcare costs in two workplace samples. J Occup Environ Med 2008;50:8898.
24 . Morrisroe K, Sudararajan V, Stevens W, Sahhar J, Zochling J, Roddy J, et al. Work productivity in systemic sclerosis, its economic burden and association with health-related quality of life. Rheumatology (Oxford) 2018;57:7383.
25 . Puolakka K, Kautiainen H, Möttönen T, Hannonen P, Hakala M, Korpela M, et al.; FIN-RACo Trial Troup. Predictors of productivity loss in early rheumatoid arthritis: a 5 year follow up study. Ann Rheum Dis 2005;64:130133.
26 . Al Dhanhani AM, Gignac MAM, Beaton DE, Su J, Fortin PR. Work factors are associated with workplace activity limitations in systemic lupus erythematosus. Rheumatology (Oxford) 2014;53:20442052.
27 . Jetha A, Badley E, Beaton D, Fortin PR, Shiff NJ, Gignac MAM. Unpacking early work experiences of young adults with rheumatic disease: an examination of absenteeism, job disruptions, and productivity loss. Arthritis Care Res (Hoboken) 2015;67:12461254.
28 . Sharif R, Mayes MD, Nicassio PM, Gonzalez EB, Draeger H, McNearney TA, et al. Determinants of work disability in patients with systemic sclerosis: a longitudinal study of the GENISOS cohort. Semin Arthritis Rheum 2011;41:3847.
29 . Singh MK, Clements PJ, Furst DE, Maranian P, Khanna D. Work productivity in scleroderma: analysis from the University of California, Los Angeles scleroderma quality of life study. Arthritis Care Res (Hoboken) 2012;64:176183.
30 . Tamborenea MN, Pisoni C, Toloza S, Mysler E, Tate G, Pereira D, et al. Work instability in rheumatoid arthritis patients from Argentina: prevalence and associated factors. Rheumatol Int 2015;35:107114.
31 . Bérezné A, Seror R, Morell-Dubois S, de Menthon M, Fois E, Dzeing-Ella A, et al. Impact of systemic sclerosis on occupational and professional activity with attention to patients with digital ulcers. Arthritis Care Res (Hoboken) 2011;63:277285.
32 . Noben C, Vilsteren MV, Boot C, Steenbeek R, Schaardenburg DV, Anema JR, et al. Economic evaluation of an intervention program with the aim to improve at-work productivity for workers with rheumatoid arthritis. J Occup Health 2017;59:267279.
33 . de Jong PHP, Hazes JM, Buisman LR, Barendregt PJ, van Zeben D, van der Lubbe PA, et al. Best cost-effectiveness and worker productivity with initial triple DMARD therapy compared with methotrexate monotherapy in early rheumatoid arthritis: cost-utility analysis of the tREACH trial. Rheumatology (Oxford) 2016;55:21382147.
34 . Olofsson T, Petersson IF, Eriksson JK, Englund M, Nilsson JA, Geborek P, et al.; ARTIS Study Group. Predictors of work disability after start of anti-TNF therapy in a national cohort of Swedish patients with rheumatoid arthritis: does early anti-TNF therapy bring patients back to work? Ann Rheum Dis 2017;76:12451252.
35 . Kim D, Kaneko Y, Takeuchi T. Importance of obtaining remission for work productivity and activity of patients with rheumatoid arthritis. J Rheumatol 2017;44:11121117.
36 . Zhang W, Bansback N, Kopec J, Anis AH. Measuring time input loss among patients with rheumatoid arthritis: validity and reliability of the Valuation of Lost Productivity questionnaire. J Occup Environ Med 2011;53:530536.
37 . Fisher JH, Kolb M, Algamdi M, Morisset J, Johannson KA, Shapera S, et al. Baseline characteristics and comorbidities in the CAnadian REgistry for pulmonary fibrosis. BMC Pulm Med 2019;19:223.
Correspondence and requests for reprints should be addressed to Christopher J. Ryerson, M.D., St. Paul’s Hospital, Respiratory Division, Room 8446-8B, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6 Canada. E-mail: .

*K.A.J. is Associate Editor and C.J.R. is Deputy Editor of AnnalsATS. Their participation complies with American Thoracic Society requirements for recusal from review and decisions for authored works.

The Canadian Registry for Pulmonary Fibrosis is funded by Boehringer Ingelheim. The sponsor had no involvement in the conception, design, analysis, or presentation of this substudy.

Author Contributions: M.A., M.S., and C.J.R. conceived and designed the study. M.A., S.G., and C.J.R. performed the data analysis. M.A., M.S., J.H.F., J.M., K.A.J., C.D.F., M.K., H.M., G.C., A.S.G., A.J.H., N.H., N.K., S.S., T.T., P.G.W., S.G., and C.J.R. participated in data acquisition, data interpretation, and the manuscript preparation. All authors approved the final version to be published.

This article has a related editorial.

This article has an online supplement, which is accessible from this issue’s table of contents at

Author disclosures are available with the text of this article at

Comments Post a Comment

New User Registration

Not Yet Registered?
Benefits of Registration Include:
 •  A Unique User Profile that will allow you to manage your current subscriptions (including online access)
 •  The ability to create favorites lists down to the article level
 •  The ability to customize email alerts to receive specific notifications about the topics you care most about and special offers
Annals of the American Thoracic Society

Click to see any corrections or updates and to confirm this is the authentic version of record