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 Finnish hospital discharge register data, including each inpatient episode 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 the hospital discharge register. Trends in the incidence of hospitalizations for malignant neoplasms were also analyzed, although <10% of hysterectomies are due to gynecological malignancies. Hospitalizations for leiomyoma, endometriosis and bleeding disorders have statistically increased, significantly, among women aged 45 years or more between 1971 and 1986, whereas hospitalizations for prolapse and malignant neoplasms did not show a significant change. Probable incidence of hysterectomy before 1986 was estimated on the basis of the annual incidence of hospitalization for leiomyoma, and hysterectomy for leiomyomas was estimated from the hospital discharge register data of 1988. According to hospital discharge data in 1988, 90% of the hospitalized women with leiomyoma underwent hysterectomy and half of the hysterectomies were performed for leiomyoma. The estimated incidence of hysterectomy increased 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 indications leading to hysterectomy is poorly known, epidemiological studies should consider the determinants of the occurrence of indications independently whether hysterectomy has been performed or not.