Differences in Self-Reported Health in the Osteoarthritis Initiative (OAI) and Third National Health and Nutrition Examination Survey (NHANES-III)

William M Reichmann,Jeffrey N Katz,Elena Losina,Joel Gagnier

doi:10.1371/journal.pone.0017345

William M Reichmann, Jeffrey N Katz + Show 2 more

Open Access

https://doi.org/10.1371/journal.pone.0017345

Copy DOI

Abstract

ObjectiveTo assess self-reported health status (SRHS) in two cohorts of participants with radiographic knee osteoarthritis (OA) and examine the extent that differences in SRHS are due to study design.MethodWe used data from the Third National Health and Nutritional Examination Survey (NHANES-III; population-based national survey) and the Osteoarthritis Initiative (OAI; prospective cohort study). Inclusion criteria for this analysis were age 60–79 and presence of radiographic knee OA. SRHS, elicited as a five-item domain (excellent, very good, good, fair, poor), was analyzed by dichotomizing the general health status measure as “fair/poor” versus all other states. We estimated the proportion of participants in fair/poor health from each study. Propensity score methodology was used to adjust for the differences in sampling strategies between the two studies.ResultsThirty-four percent (N = 1,608) of OAI and 29% (N = 756) of NHANES-III participants satisfied inclusion criteria. The proportion in fair/poor health was higher in NHANES-III (28%) than in OAI (5%). After adjusting for the propensity score, the proportion in fair/poor health was four times higher in NHANES-III than in OAI.ConclusionSRHS was substantially better in OAI than in NHANES-III. Self-selection bias may contribute to overestimation of SRHS in prospective cohort studies such as OAI.

Highlights

Knee osteoarthritis (OA) is a prevalent and disabling disease that primarily affects the elderly
Self-reported health status (SRHS) was substantially better in Osteoarthritis Initiative (OAI) than in NHANES-III
Self-selection bias may contribute to overestimation of SRHS in prospective cohort studies such as OAI

Summary

Introduction

Knee osteoarthritis (OA) is a prevalent and disabling disease that primarily affects the elderly. Studies have shown that knee OA greatly diminishes health status in the elderly [4,5]. Self-reported health status (SRHS) is a subjective measure of how one perceives and reports his or her own well-being. SRHS is often measured by asking individuals to rate their health as excellent, very good, good, fair, or poor. This type of self-reported information is considered an important indicator of a person’s health status [6]. It has been shown to be a stable measure of one’s health and to be associated with the number of physician contacts [7] and mortality [7,8]. Often SRHS is measured in national surveys to monitor population health and this measure has been used in the United States [8], Canada [6], England [9], and Australia [10]

Methods

Results

Conclusion