Association between use of air-conditioning or fan and survival of elderly febrile patients: a prospective study

Elderly individuals are more susceptible to excess summer heat. We sought to examine whether the use of cooling systems (air-conditioning or fan) affected the clinical outcomes of elderly febrile patients. We prospectively followed elderly (≥75 years old) febrile patients requesting the medical services of the SOS Doctors (a network of physicians performing house-call visits) from July 10 to August 20, 2011. Patients who used cooling systems (“users”) were compared with those who did not (“non-users”) regarding mortality, clinical outcome of primary illness (improvement or deterioration), and emergency hospitalization. Prospectively collected data were available for 339 individual elderly febrile patients. “Users” had lower mortality (10 % vs. 19 %, p < 0.05) than “non-users”; no difference was noted on clinical improvement (85 % vs. 76 %, p = 0.11) and emergency hospitalization rates (21 % vs. 30 %, p = 0.16). No difference was noted between users of air-conditioning and fan regarding mortality or clinical improvement, but fan use was associated with more hospitalizations (37 % vs. 19 %, p < 0.05). On multivariate analysis (assessing daily ambient temperature, use of cooling systems, patient age, and living conditions), the sole variable significantly associated with mortality was the non-use of cooling systems [odds ratio (OR): 2.18, 95 % confidence interval (CI): 1.06–4.50]. The use of air-conditioning or fan during hot summer periods appeared to be beneficial for elderly febrile patients living in a large city. Large prospective studies are warranted in order to provide further insight into potential individual and public health initiatives aiming to alleviate the impact of excess summer heat on the health of elderly patients.