Background and objective: The relationship between anticholinergic burden and mortality is unclear, and the impact of anticholinergic burden on prognosis may vary in the presence of other conditions common in old age. We aimed to investigate the role of hand grip strength as a potential effect modifier in the association between anticholinergic burden and 1-year mortality in older patients discharged from hospital.
Methods: Our series consisted of 620 older patients consecutively admitted to seven geriatric and internal medicine acute care wards in the context of a prospective multicenter observational study. Overall anticholinergic burden was assessed by Anticholinergic Cognitive Burden (ACB) score. Hand grip strength was assessed by the use of a North Coast medical hand dynamometer and categorized by using sex-specific cut-offs (women < 15 kg, men < 20 kg). The study outcome was 1-year mortality. Statistical analysis was performed by Cox regression analysis.
Results: After adjusting for potential confounders, the co-occurrence of an ACB score of 2 or more and low hand grip strength was significantly associated with mortality (hazard ratio [HR] = 2.30, 95% confidence interval [CI] 1.07-6.01). Stratified analysis confirmed that an ACB score of 2 or more was associated with mortality among patients with low (HR = 2.15, 95% CI 1.08-5.02), but not normal hand grip strength (HR = 0.88, 95% CI 0.13-3.52). The association was confirmed among patients with low hand grip strength after adjusting for the ACB score at the 3-month follow-up (HR = 2.20; 95% CI 1.09-4.87), as well as when considering the ACB score as a continuous variable (HR = 1.24, 95% CI 1.03-1.48).
Conclusions: The ACB score at discharge may predict mortality among older patients discharged from an acute care hospital with low hand grip strength. Hospital physicians should be aware that prescribing anticholinergic medications in such a vulnerable population may have negative prognostic implications.