The frequency and factors linked to a urinary tract infection coding in patients undergoing hip fracture surgery

Abstract

Objective: To study the frequency and factors linked to having an International Classification of Diseases, Ninth Revision (ICD-9) diagnosis of urinary tract infection (UTI) in patients undergoing hip fracture surgery.

Methods: A retrospective observational study of a cohort of all patients admitted to a university teaching hospital with a principal ICD-9 diagnosis of a hip fracture during 3 consecutive calendar years.

Results: A total of 138 subjects (67% were 65 years or older) underwent hip fracture surgery during the study period. Twelve percent of subjects had an ICD-9 UTI diagnosis during the hospitalization period. The incidence of UTI diagnosis was greater in subjects who were 65 years or older compared with younger subjects (16% vs 4%, P < .05), females compared with males (18% vs 5%, P < .05), subjects admitted to a medical floor compared with subjects admitted to a surgical floor (45% vs 10%, P < .001), and in subjects with biochemical evidence of dehydration on admission compared with those without such evidence (20% vs 7%, P < .05). The incidence of an ICD-9 UTI diagnosis correlated positively with the number of days subjects received nothing per mouth (NPO) after surgery (P < .0001). Subjects who had a UTI diagnosis scored higher on the Goldman Cardiac Risk index (P < .05) indicating they were sicker. Using logistic regression analysis, only the number of days a patient was kept NPO after surgery was an independent predictor of having a UTI diagnosis (B = -1.34, P = .043). Presence of biochemical evidence of dehydration on admission was another possible predictor with a P value approaching significance (B = 0.3, P = .07). Subjects with a UTI diagnosis had longer mean (+/- SD) length of hospital stay (8.7 +/- 8 vs 5.4 +/- 3 days, P < .05) and greater incidence of delirium (35% vs 8%, P < .0001) compared with subjects without a UTI diagnosis.

Conclusions: Urinary tract infection ICD-9 diagnosis is frequent among patients undergoing hip fracture surgery and is linked to prolonged length of hospital stay and to increased incidence of delirium. Number of days patients were kept off oral intake after surgery was an independent factor associated with a UTI diagnosis during the hospitalization period in this patient population.