Prospective cohort study of fever incidence and risk in elderly persons living at home.

Objective: To determine the incidence of fever among elderly persons under home medical management, diagnosis at fever onset and outcomes from a practical standpoint.

Design: Prospective cohort study.

Setting: 5 clinics in residential areas of Tokyo that process an average of 50-200 outpatients/day.

Participants: Patients (n=419) aged ≥65 years who received home medical management from the five clinics between 1 October 2009 and 30 September 2010.

Main Outcome Measures: Fever (≥37.5°C or ≥1.5°C above usual body temperature), diagnosis at onset and outcomes (cure at home, hospitalisation and death).

Results: The incidence of fever was 2.5/1000 patient-days (95% CI 2.2 to 2.8). Fever occurred at least once (229 fever events) among one-third of the participants during the study period. Fever was more likely to arise in the wheelchair users or bedridden than in ambulatory individuals (HR 1.9 (95% CI 1.3 to 2.8; p<0.01); in patients with moderate-to-severe rather than those with none-to-mild cognitive impairment (HR, 1.7 (95% CI 1.1 to 2.6, p=0.01); and in those whose care-need levels were ≥3 rather than ≤2 (HR, 4.5 (95% CI 2.9 to 7.0; p<0.01). The causes of fever were pneumonia/bronchitis (n=103), skin and soft tissue infection (n=26), urinary tract infection (n=22) and the common cold (n=13). Fever was cured in 67% and 23% of patients at home and in hospital, respectively, and 5% of patients each died at home and in hospital. Antimicrobial agents treated 153 (67%) events in the home medical care setting.

Conclusions: Fever was more likely to occur in those requiring higher care levels and the main cause of fever was pneumonia/bronchitis. Healthcare providers should consider the conditions of elderly residents with lower objective functional status.