Association between frailty and pain in older people at high risk of future hospitalization.

Background: Previous studies have demonstrated an independent association between pain and frailty, but knowledge about this association with different pain characteristics is limited.

Objective: This study was embedded in a prospective, pragmatic, matched-control multicenter trial at 19 primary care practices in south-eastern Sweden (ClinicalTrials.gov 170608, ID: NCT03180606), aiming to investigate the association between frailty and pain characteristics among older people (75+) at high risk of hospitalization.

Methods: High risk of hospitalization was identified using case-finding algorithm including 32 diagnostic codes of morbidities and healthcare use. Frailty was assessed by a nurse-physician team using Clinical Frailty Scale (N = 389). Data on pain aspects, physical and ADL functioning were collected in the self-reported questionnaires.

Results: One in three (n = 133, 34%) was classified as frail. About 36% (n = 142) reported frequent pain (from several times per week to constantly). Slightly over 40% reported pain lasting longer than 3 months (n = 163, 41.9%) and/or having regional or widespread pain (n = 165, 42.4%). In comparison to non-frail peers, frail participants reported higher pain intensity, more ADL-dependency, less physical activity, and more anxiety/depression (p < 0.01). In logistic regression analysis, pain frequency [Odds Ratio (OR) 1.8, 95% confidence interval (CI): 1.2-2.8] was associated with frailty. However, the models with ADL-staircase score (OR: 1.4, 95% CI: 1.2-1.6) had a higher explanatory power (Nagelkerke R ²: 0.39) in predicting frailty than those without this aspect (R ²: 0.10 and 0.13).

Conclusion: In older people at high risk of hospitalization, pain frequency seemed to be related to frailty, whilst ADL dependency demonstrated a stronger association.