Severity assessment of lower respiratory tract infection in elderly patients in primary care.

BACKGROUND Simple markers for evaluating the severity of lower respiratory tract infections (LRTI) in primary care are lacking. It is of value to examine whether the information available to the primary care physician during a patient's initial visit can be used to assess the severity of LRTI. METHODS The associations between different baseline variables and outcomes (survival within or more than 30 days) were investigated prospectively in a series of 950 home-living patients 65 years or older with severe LRTI that their primary care physicians suspected to be pneumonia. RESULTS Twenty-one men and 17 women died (4.1%) within 30 days. According to univariate analysis, the following parameters differed (P < .01) between the fatalities and survivors: acute aggravation of a coexisting illness, age, respiratory rate, white blood cell count, and C-reactive protein (CRP) level. According to Cox forward stepwise regression analysis (P = .01 for entry and.05 for removal), acute aggravation of a concurrent illness, respiratory rate (> or = 25/min), and CRP concentration (> or = 100 mg/L) were independently associated with death. The mortality rate was 2.2% if the patients had none or only 1 of the independent risk factors and 20% if they had all 3 risk factors. CONCLUSIONS Preceding aggravation of a concurrent illness and respiratory rate of 25/min or higher, together with an elevated serum CRP level (> or = 100 mg/L), can be used as simple markers for identifying patients with the highest risk for LRTI and improve management decisions among elderly people in primary care.