Effect of social factors on winter hospital admission for respiratory disease: a case-control study of older people in the UK.

BACKGROUND: Every winter, hospitals in the UK and other developed countries experience a surge in respiratory admissions. Ecological studies suggest that social circumstances may be an important determinant. AIM: To establish the most important factors associated with winter hospital admissions among older people presenting with acute respiratory disease, especially the relative effect of social factors. DESIGN OF STUDY: case-control study. SETTING: Seventy-nine general practices in central England. METHOD: Of a cohort of patients consulting medical services with lower respiratory tract infection or exacerbation of chronic respiratory disease, 157 hospitalised cases were compared to 639 controls. Social, medical, and other factors were examined by interview and GP records. RESULTS: Measures of material deprivation were not significant risk factors for admission at either individual or area level, although social isolation (odds ratio [OR] 4.5; 95% confidence interval [CI] = 1.3 to 15.8) resulted in an increased risk of admission. The most important independent risk factor was the presence of chronic obstructive pulmonary disease (COPD; OR 4.0; 95% CI = 1.4 to 11.4), other chronic disease (OR 2.9; 95% CI = 1.2 to 7.0), or both (OR 6.7; 95% CI = 2.4 to 18.4). Being housebound was also an independent risk factor (OR 2.2; 95% CI = 1.0 to 4.8). CONCLUSION: Socioeconomic factors had little relative effect compared with medical and functional factors. The most important was the presence of long-term medical conditions (especially COPD), being housebound, and having received two or more courses of oral steroid treatment in the previous year. This combination of factors could be used by primary medical services to identify older patients most vulnerable to winter admissions. Clinicians should ensure that patients with COPD are better supported to manage their condition.