Anticipated significant work limitation in primary care consulters with osteoarthritis: a prospective cohort study

Objective To describe the prevalence of expected work limitations (EWL) prior to future retirement age in osteoarthritis consulters, and the associated health, sociodemographic and workplace factors. Design Population-based prospective cohort study. Setting General practices in Staffordshire, England. Participants 297 working adults aged 50–65, who had consulted primary care for osteoarthritis. Outcome EWL was defined using a single question, “Do you think joint pain will limit your ability to work before you reach 69 years old?” Results 51 (17.2%) indicated that joint pain would not limit their ability to work until 69, 79 (26.6%) indicated EWL and 167 (56.2%) did not know if joint pain would limit work before 69. In bivariate analysis, physical function (OR 0.93; 95% CI 0.91 to 0.96), depression (4.51; 1.81 to 11.3), cognitive symptom (3.84; 1.81 to 8.18), current smoker (2.75; 1.02 to 7.38), age (0.69; 0.58 to 0.82), physically demanding job (3.18; 1.50 to 6.72), no opportunities to retrain (3.01; 1.29 to 7.05) and work dissatisfaction (3.69; 1.43 to 9.49) were associated with EWL. The final multivariate model included physical function and age. Conclusions Only one in five osteoarthritis consulters expected that joint pain would not limit their work participation before 69 years of age. Given the expectation for people to work until they are older, the results highlight the increasing need for clinicians to include work participation in their consultation and implement strategies to address work loss/limitation. Targeting pain-related functional limitation and effective communication with employers to manage workplace issues could reduce EWL.


Introduction
• To-the point • Relevant and up to date references Methods • I found it a bit confusing what parameter is measured at exactly what point in time after inclusion of the participant. Could you please provide a table or figure to get a better overview? • Page 6, line 22, I think that although the p-value=0.052 the group non responders on EWL differ considerably from the responders. I would have added this to the 'more likely to be' instead of 'no more likely to be'. Please address this in the discussion. • Page 8, line 8, Read=READ • Page 8, line 24, … and weight was (or were?)… • Please use one phrase for 'demographic and socio-economic' throughout the paper. Now it differs for instance 'socio-demographic' or 'socio-economic'. • Page 9, line 3: please also provide an example for 'routine' • Page 10, line 13: I find it informative to get information about the explained variance of the multivariate regression models. Is that manageable?  Table 2 o Is it possible to make the significant ORs more visible for instance printing them bold or using symbols? o As said, is it informative to present also the explained variance?

Results
• Figure 1 o No comment Again, an informative and well written paper on a topic that needs more attention of professionals in primary and secondary care.
Hopefully my comments are clear and of use for the authors.

REVIEWER
Carol Coole University of Nottingham UK REVIEW RETURNED 30-Jun-2014

GENERAL COMMENTS
Thank you for inviting me to review this paper, which reads well and is a subject of importance to a range of stakeholders. I recommend it should be published subject to some very minor changes.
Work loss/limitation: sometimes the term 'work loss' is used alone in the text when referring to the outcome measure, rather than 'work loss/limitations'.

Method
The method of measuring pain seems to be measuring the site of pain rather than the degree of painthe latter might have a different association with physical function.
Illness perception and beliefs have not been measured, and there are no references to these factors. which could have a considerable impact on EWLand be an area to be addressed with patients, GPs and employers in the management of osteoarthritis in the workplace.
Independent factorscould the authors clarify what is meant by 'health factors being measured across the six year study period', also 'workplace factors were measured retrospectively'.
Health factorsif these were being measured across the six year study period, could the authors explain why the three year follow up score was used, rather than the six year score.
Occupational classificationit would help the reader to have an explanation of 'intermediate' and 'routine' occupations.

Method/Results
What was the extent of missing data for other measures, and how was this dealt with?

Discussion
Second paragraph. The reference to Theis and Murphy implies that the current study has measured reported work limitations. The claim made in the introductory sentence isn't supported. Suggest revising the paragraph.
Third paragraphlast sentencesuggest the authors clarify what 'this' refers to each time.

VERSION 1 -AUTHOR RESPONSE
Reviewer: Paul Kuijer Methods 1. Could you please provide a table or figure to get a better overview of when things were measured? Response: We have included a table which outlines when the outcome and potential predictors were measured (please see Table 1). We have also added a sentence in the methods explaining that the identification of consulters with osteoarthritis occurred across the study period. 2. Page 6, line 22, I think that although the p-value=0.052 the group non responders on EWL differ considerably from the responders. I would have added this to the 'more likely to be' instead of 'no more likely to be'. Please address this in the discussion. Response: We agree the initial interpretation is based on the empirical cut-off of 0.05 for significance. We have amended the manuscript (revised manuscript with track changes page 6, para 1). We have alluded to this in the discussion; despite responders being more likely to have an adequate income compared to those who dropped out, income adequacy, or any of the other socio-economic variables were significantly associated with EWL in this study. We expect the level of non-response bias would be minimal. 7. Page 13, line 22: could you be more specific than 'If this changes in the future the implications of this will increase.' Response: We have revised this sentence (page 13, para 1). 8. Page 14, line 12-15 '… current workplace status at the same time that question on anticipated EWL was asked and page 14, line 43-46, '… and workplace problems were present well in advance of when EWL was measured'. Are these two statements in line? Response: The questions on EWL and workplace factors were all measured at 6 years. We agree that some of the workplace factors may not have been present well in advance of this time point and have removed reference to the workplace in this sentence. 9. Page 16, line 10: The two recent papers of Kievit AJ et al. about a specific questionnaire (Work, Osteoarthritis or joint-Replacement Questionnaire -WORQ) to assess problems performing knee demanding work in patients with osteoarthritis of the knee might be a nice example of a recent development in screening: Response: We have added these references to the paper (page 15 para 2) 10. Conclusion: Page 16, Address also the second aim of the study about factors that predict EWL, see for instance your conclusion in the abstract.