Social conditions impact functional outcome in patients with hand osteoarthritis: the low-income hand osteoarthritis (LIHOA) cohort

Abstract

Background Hand osteoarthritis (HOA) is a highly prevalent disease that may be impacted by social inequalities. Few studies in HOA are from underdeveloped regions. We intend to contribute to fill this gap presenting clinical characteristics of our low-income HOA cohort (LIHOA). Methods Data from 119 patients with a HOA diagnosis fulfilling ACR criteria seen between August 2019 and May 2023 in Fortaleza/Brazil. Evaluations included pain (VAS, visual analogue scale), X-ray (KL, Kellgren-Lawrence), grip and pinch strength (KgF), Cochin hand functional scale (CHFS), FIHOA, and SF-12 scores. Social data included monthly (<1, 1≥/<3, ≥3 MW) minimum wage earnings, occupation, and literacy [</≥ 9 school-years (SY)]. Results 107 out of the 119 patients were included. Mean age was 61.9 (±10.3) years with 94 (92%) women. Systemic arterial hypertension (48%), metabolic syndrome (42.8%), dyslipidemia (28.4%), and obesity (25%) were the most common comorbidities. Mean disease duration was 7.5 ± 7.1 years. Median VAS values at rest and activity were 3 (3–5) and 8 (5–9), respectively (p < 0.001). Fifty-seven (56.4%) patients had ≥4 symptomatic joints with a median of 4 (2–8) painful joints at activity. The 2nd distal interphalangeal (IF), joint was the most symptomatic (21; 23.3%) and most had >4 IF nodes. OA in other joints: 37 (36.2%) spine, 28 (29.4%) knee, 21 (20.5%) bunions. Functional impairment was mild [8 (5–14) median FIHOA]. Median serum CRP was 0.2 mg/dL (0.1–0.4) with 14 (20%) patients above reference value. Mean total KL score was 27.6 ± 13.6 with 21 (23%), 38 (41.7%), and 33 (36.2%) KL2, KL3, and KL4, respectively; 51 (54.8%) and 42 (45.2%) patients declared </≥3 MW earnings, respectively. Most declared >9SY including 37.2% with a university degree. Individuals earning <3 MW had lower pinch (p < 0.004) and grip strength (p < 0.01), and higher FIHOA scores (p < 0.007), as compared to ≥3 MW earning group. Literacy or occupation did not impact outcome. SYSADOA were used by 13 (12.7%), 6 used oral and 3 topical anti-inflammatory drugs and 2 used 5 mg/d prednisone. Conclusion Clinical characteristics in our LIHOA cohort mirror those reported in affluent regions. Socioeconomic disparities influenced functional outcome in LIHOA cohort.