Hysterectomy with and without oophorectomy and all-cause and cause-specific mortality

BACKGROUND: Hysterectomy is one of the most commonly performed gynecologic surgeries, with an estimated 30% of women in Australia undergoing the procedure by age of 70 years. In the United States, about 45% of women undergo hysterectomy in their lifetime. Some studies have suggested that this procedure increases the risk of premature mortality. With many women making the decision to undergo hysterectomy for a benign indication each year, additional research is needed to clarify whether there are long-term health consequences of hysterectomy. OBJECTIVE: This study aimed to examine the association between hysterectomy for benign indications, with or without removal of the ovaries, and cause-specific and all-cause mortality. STUDY DESIGN: Our cohort of 666,588 women comprised the female population of Western Australia with linked hospital and health records from 1970 to 2015. Cox regression models were used to assess the association between hysterectomy and all-cause, cardiovascular disease, cancer, and other mortality by oophorectomy type (categorized as none, unilateral, and bilateral), with no hysterectomy or oophorectomy as the reference group. We repeated these analyses using hysterectomy without oophorectomy as the reference group. We also investigated whether associations varied by age at the time of surgery, although small sample size precluded this analysis in women who underwent hysterectomy with unilateral salpingo-oophorectomy. In our main analysis, women who underwent hysterectomy or oophorectomy as part of cancer treatment were retained in the analysis and considered unexposed to that surgery. For a sensitivity analysis, we censored procedures performed for cancer. RESULTS: Compared with no surgery, hysterectomy without oophorectomy before 35 years was associated with an increase in all-cause mortality (hazard ratio, 1.29; 95% confidence interval, 1.19-1.40); for surgery after 35 years of age, there was an inverse association (35-44 years: hazard ratio, 0.93; 95% confidence interval, 0.89-0.97). Similarly, hysterectomy with bilateral salpingo-oophorectomy before 45 years of age was associated with increased all-cause mortality (35-44 years: hazard ratio, 1.15; 95% confidence interval, 1.04-1.27), but decreased mortality rates after 45 years of age. In our sensitivity analysis, censoring gynecologic surgeries for cancer resulted in many cancer-related deaths being excluded for women who did not have surgery for benign indications and thus increased the hazard ratios for the associations between both hysterectomy without oophorectomy and hysterectomy with bilateral salpingo-oophorectomy and risk of all-cause and cancer-specific mortality. The sensitivity analysis therefore potentially biased the results in favor of no surgery. CONCLUSION: Among women having surgery for benign indications, hysterectomy without oophorectomy performed before 35 years of age and hysterectomy with bilateral salpingo-oophorectomy performed before 45 years of age were associated with an increase in all-cause mortality. These procedures are not associated with poorer long-term survival when performed at older ages.