5 GYNECOLOGIC DIAGNOSES ASSOCIATED WITH HYSTERECTOMY - TRENDS IN INCIDENCE OF HOSPITALIZATIONS IN FINLAND, 1971-1986

Trends in hospitalizations for selected gynecologic diagnoses per 100 000 women/year associated with hysterectomy were analyzed using the Fi nnish hospital discharge register data, including each inpatient episo de in all Finnish hospitals, from 1971 to 1986. The diagnoses selected were uterine leiomyoma, genital prolapse, the group 'other disorders of the uterus' including endometriosis, and bleeding disorders. These were the most common indications for hysterectomy in Finland from 1987 to 1989, when national data on surgical procedures were included in t he hospital discharge register. Trends in the incidence of hospitaliza tions for malignant neoplasms were also analyzed, although <10% of hys terectomies are due to gynecological malignancies. Hospitalizations fo r leiomyoma, endometriosis and bleeding disorders have statistically i ncreased, significantly, among women aged 45 years or more between 197 1 and 1986, whereas hospitalizations for prolapse and malignant neopla sms did not show a significant change. Probable incidence of hysterect omy before 1986 was estimated on the basis of the annual incidence of hospitalization for leiomyoma, and hysterectomy for leiomyomas was est imated from the hospital discharge register data of 1988. According to hospital discharge data in 1988, 90% of the hospitalized women with l eiomyoma underwent hysterectomy and half of the hysterectomies were pe rformed for leiomyoma. The estimated incidence of hysterectomy increas ed from 311/100 000 women to similar to 400/100 000 from 1971 to 1986 (slope = 6.5 hysterectomies/100 000/year; 95% C.I. for slope (4.8:8.2) ). As the epidemiology of most of the underlying disorders for indicat ions leading to hysterectomy is poorly known, epidemiological studies should consider the determinants of the occurrence of indications inde pendently whether hysterectomy has been performed or not.