Incidence and clinical characteristics of National Institutes of Health type III prostatitis in the community

Purpose: Few population based epidemiological studies of prostatitis have been performed. We used coded physician diagnoses and subsequent chart reviews to estimate the incidence and clinical characteristics of physician diagnosed National Institutes of Health (NIH) type III prostatitis. Materials and Methods: Computer searches of the Kaiser Permanente Northwest (Portland, Oregon) database were performed on the 2-year interval May 2002 to May 2004 to identify new diagnoses of chronic prostatitis (International Classification of Diseases, 9th Revision code 601.1) and prostatitis not otherwise specified (International Classification of Diseases, 9th Revision code 601.9). Of the 1,223 men identified with these coded diagnoses, chart reviews were performed on a random subset of 413 (33.8%). Patients were categorized based on NIH prostatitis definitions of type I/II-evidence of pyuria and/or bacteriuria on urinalysis or culture, type III-presence of at least 1 of the pain or urinary symptoms in the NIH Chronic Prostatitis Symptom Index (pain in the perineum, testicles, tip of penis, pubic or bladder area, dysuria, ejaculatory pain, incomplete emptying, urinary frequency), type IV-inflammation on prostate biopsy and Other-symptoms other than those listed. Results: Of the 413 patients 57 were previously diagnosed with prostatitis (prevalent cases), 46 had no evidence of a prostatitis diagnosis in the medical record and 7 were treated by physicians outside of the Kaiser Permanente Northwest plan. Of the remaining 303 the distribution was 58 type I/II, 189 type III, 33 type IV and 23 Other. The incidence of physician diagnosed type III prostatitis was 3.3 per 1,000 person-years. If those with isolated urinary symptoms were excluded from analysis, the incidence decreased to 2.8 per 1,000 person-years. The mean age of those with type III prostatitis was 52.9 years (range 29 to 82). The most common presenting symptoms were dysuria, urinary frequency and perineal pain. Symptom duration at presentation was less than 3 months in 44%, 3 months or greater in 31% and unspecified in 25%. The majority (78%) of new prostatitis diagnoses was made by primary care physicians. Conclusions: These data indicate that prostatitis is commonly diagnosed in the community setting, and that type III prostatitis accounts for the majority of these diagnoses. The duration and complexity of symptoms are less than those reported in established prostatitis research cohorts. Most prostatitis diagnoses in the community are made by nonurologists.