Use of a prostate symptom score to identify men at risk of future kidney failure: insights from the HUNT II Study

Abstract

Background: Chronic kidney disease (CKD) screening beyond patients with diabetes mellitus or hypertension increasingly is discussed. Some guidelines recommend kidney function testing of patients with benign prostatic hyperplasia; however, the significance of extending this to general population screening is unclear.

Study design: Prospective cohort study.

Setting & participants: 30,466 men from the HUNT II (Second Health Study in Nord-Trøndelag; 1995-1997) representing 66.8% of the entire adult male population in Nord-Trøndelag County, Norway.

Predictor: The International Prostate Symptom Score was used to detect the presence and severity of lower urinary tract symptoms (LUTS), a surrogate measure of benign prostate hyperplasia suitable for use in general practice.

Outcomes: Kidney failure was defined as starting renal replacement therapy or CKD death with a documented stable estimated glomerular filtration rate<15 mL/min/1.73 m2.

Results: During 10.5 years of follow-up, 78 men developed kidney failure. Kidney failure risks were 2.60 (95% CI, 1.47-4.58) and 4.08 (95% CI, 1.74-9.53) times higher for men with moderate and severe LUTS compared with men with no/mild LUTS, respectively. However, age-stratified analysis showed that the incidence rate ratio for moderate/severe LUTS versus no/mild LUTS was 1.27 (95% CI, 0.76-2.13), and multivariable Cox analysis showed no significant association between LUTS and risk of kidney failure. Screening effectiveness was improved only slightly by including men with moderate/severe LUTS in addition to patients with diabetes, hypertension, or cardiovascular disease. Better effectiveness was achieved by simply including all men older than 60 years.

Limitations: The ability of the International Prostate Symptom Score to predict the presence and severity of obstruction is only moderate. Ascertainment of severe CKD (estimated glomerular filtration rate, 30-15 mL/min/1.73 m2) was not possible.

Conclusion: LUTS were not significantly associated with future kidney failure after adjusting for age and therefore in isolation are not a basis for kidney failure screening.