Associations of current and childhood socioeconomic status and health outcomes amongst patients with knee or hip osteoarthritis in a Mexico City family-practice setting.

OBJECTIVES

To examine the association of current and childhood socioeconomic status (SES) with patient-reported functional status, quality of life and disability in patients with knee or hip osteoarthritis (OA).

METHODS

Cross-sectional study amongst individuals seeking care for any medical reason in a primary care family-practice clinic in Mexico City. We included individuals with self-reported doctor-diagnosed arthritis, recruited through waiting-room posters and invitations by treating family physicians. We administered a survey using validated Spanish language versions of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Osteoarthritis of Lower Limbs and Quality of Life (AMICAL), and the Stanford Health Assessment Questionnaire-Disability Index (HAQ-DI). To estimate current and childhood SES, we collected data on education level and occupation type for both the patient and their parents, as well as using a validated tool to estimate income quintile.

RESULTS

We recruited 154 patients and excluded 8 patients. There was a high correlation between outcome scores. Estimated income and education levels were correlated with WOMAC, AMICAL and HAQ-DI scores, and significant differences were found in all scores by occupation type. The associations for current SES variables and outcome scores remained significant independently of age, sex, BMI, and presence of diabetes or hypertension, and were largely explained by current income in mutually adjusted models. Childhood SES - in particular as measured through maternal education - was best correlated with AMICAL scores, though its effect seemed largely mediated by its association with current SES.

CONCLUSIONS

Current Socioeconomic Status impacts functional status, quality of life and disability amongst OA patients in Mexico City. The WOMAC, AMICAL and HAQ-DI scores correlate with each other and are all potentially useful markers of disease severity. More research is needed to elucidate the relationships between childhood SES and OA outcomes. Awareness of life-course SES may be useful in identifying patients at risk for worse outcomes.