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• Predictors of disability in valued life activities in Rheumatoid arthritis
  Meenakshi Jolly
  Published on: 8 August 2006

• Published on: 8 August 2006

  Predictors of disability in valued life activities in Rheumatoid arthritis

  • Meenakshi Jolly, Assistant Professor of Medicine

  Dear Editor,

  I read with interest the article by Katz et al on the prevalence and predictors of disability in valued life activities among individuals with rheumatoid arthritis (1).

  It is encouraging that patient based assessments are being explored among rheumatic diseases. Rheumatoid arthritis (RA) and osteoarthritis (OA) have received the most attention in this regard. It is thus reassuring that...

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  Dear Editor,

  I read with interest the article by Katz et al on the prevalence and predictors of disability in valued life activities among individuals with rheumatoid arthritis (1).

  It is encouraging that patient based assessments are being explored among rheumatic diseases. Rheumatoid arthritis (RA) and osteoarthritis (OA) have received the most attention in this regard. It is thus reassuring that in this study, the Health Assessment Questionnaire (HAQ) was predictive (B 2.44 for "unable" , 6.4 for "affected" and 0.56 for "difficulty) of the overall valued activity disability.

  I have some comments and queries. The study population is comprised of individuals receiving treatment from rheumatologists, and had expressed their interest in RA research. This may be a surrogate for people with positive health behaviors, compliance and better educational status. Patients that visit a rheumatologist may not reflect the general RA patient population, as they may have better access to medical care, especially for those 65 years or older (Medicare). In such recruitment, we not only compromise generalizability of the results, but also the variation in the disease spectrum. It would have been helpful to include educational status and ethnicity data, since lower educational level is known to be associated with work disability (2). Furthermore, lower socio economic status is related with disease severity, more co morbidity and higher mortality in RA (3).

  The mean age of the study participants was 60 years and mainly comprised of women, the subgroups that also have a higher prevalence of osteoarthritis (OA). Can patients differentiate between limitations due to RA or their coexistent OA or other co-morbidities (obesity, cardiac or pulmonary disease, vision etc)? More than 50% of the subjects had one or more co-morbidities, as mentioned in Table 2; however the multiple regression models did not include co-morbidities as an independent variable in the models for VLA.

  Knowledge about the distribution of the data and range for age, duration of disease and HAQ scores would have been helpful. Standard deviations that are larger than the mean scores, on the difficulty ratings (Table 3), may suggest the presence of outliers or lack of data. Table 3, indicates the problem with fewer observations in the difficulty ratings in the last two columns for "a lot" and "unable".

  Lastly, it is not evident from the methods section about the recall period used for VLA assessments. The methods section notes a six months recall period for development of the VLA scale. However, it has since been revised as mentioned by the authors. If six month recall period was also used for this study, it may be too long a period for 60 years old patients to recall. Similarly, detail about the method used for (physician/patient) assessment of the number of swollen/painful joints would add to our knowledge, to ascertain if this is was a completely patient based assessment or included additional physician assessment.

  It would be nice to see a similar study in early RA patients, so that modifiable factors (including clinical information such as lag period between disease onset to its diagnosis, time taken to start the treatment with disease modifiers, and period between onset of disease and therapeutic remission, presence of erosions, nodules, ESR/CRP, access to health care, satisfaction with treatment, compliance, education, ethnicity)which can predict potential disability in VLA, can be determined, so that we can devise ways to prevent potential disability.

  Sincerely

  Meenakshi Jolly, MD, MS

  References

  1) Katz PP, Morris A, Yelin EH. Prevalence and predictors of disability in valued life activities among individuals with rheumatoid arthritis. Ann Rheum Dis 2006;65:763-769

  2) Morales-Romero J, Gonzalez-Lopez L, Celis B et al. Factors associated with permanent work disability in Mexican Patients with Rheumatoid Arthritis. A case control study. J Rheumatol 2006;33:1247-9

  3) Harrison MJ, Tricker KJ, Davies L et al. The relationship between social deprivation, disease outcome measures, and response to treatment in patients with stable, long standing rheumatoid arthritis. J Rheumatol 2005;32:2330-6.

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  Conflict of Interest:
  None declared.

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