Clinically diagnosed infections predict disability in activities of daily living among the oldest-old in the general population: the Leiden 85-plus Study

Background: ageing is frequently accompanied by a higher incidence of infections and an increase in disability in activities of daily living (ADL). Objective: this study examines whether clinical infections [urinary tract infections (UTI) and lower respiratory tract infections (LRTI)] predict an increase in ADL disability, stratified for the presence of ADL disability at baseline (age 86 years). Design: the Leiden 85-plus Study. A population-based prospective follow-up study. Setting: general population. Participants: a total of 154 men and 319 women aged 86 years. Methods: information on clinical infections was obtained from the medical records. ADL disability was determined at baseline and annually thereafter during 4 years of follow-up, using the 9 ADL items of the Groningen Activity Restriction Scale. Results: in 86-year-old participants with ADL disability, there were no differences in ADL increase between participants with and without an infection (−0.32 points extra per year; P = 0.230). However, participants without ADL disability at age 86 years (n = 194; 41%) had an accelerated increase in ADL disability of 1.07 point extra per year (P < 0.001). For UTIs, this was 1.25 points per year (P < 0.001) and for LRTIs 0.70 points per year (P = 0.041). In this group, an infection between age 85 and 86 years was associated with a higher risk to develop ADL disability from age 86 onwards [HR: 1.63 (95% CI: 1.04–2.55)]. Conclusions: among the oldest-old in the general population, clinically diagnosed infections are predictive for the development of ADL disability in persons without ADL disability. No such association was found for persons with ADL disability.