Study finds no link between elective surgery and dementia risk in seniors
Patients older than age 65 years who underwent elective surgeries had a 4.6% rate of incident dementia within five years, compared to 6.9% in matched controls who consulted with a surgeon but did not undergo surgery, a Canadian study found.
Elective surgery is not associated with an increased risk of incident dementia among older adults, new study results show.
Researchers carried out a population-based retrospective cohort study matching patients ages 66 years and older who underwent noncardiac elective surgeries between April 2007 and March 2011 with controls who consulted with a surgeon but did not undergo surgery. Data were gleaned from administrative databases in Ontario, Canada. Studied surgeries included hip or knee replacement, inguinal hernia repair, prostatectomy, and hysterectomy. Patients (average age, 74.1 years; 63% women) were followed for up to five years. Findings were published by the Journal of the American Geriatrics Society on Jan. 2.
At five years, patients who underwent elective surgeries had a lower rate of incident dementia than controls (hazard ratio [HR], 0.88 [95% CI, 0.80 to 0.97]; P=0.01). Of the 27,878 adults, 640 (4.6%) surgical patients developed dementia during the follow-up period compared with 965 (6.9%) controls. Both groups had a median time to dementia diagnosis of 2.3 years.
Subgroup analyses showed patients who received a regional anesthetic, underwent hip replacement surgery, were male, or were between the ages of 80 to 84 years had statistically significant lower rates of incident dementia. However, the magnitude of the lower hazard in these subgroups was small, “suggesting they may be statistically indistinguishable from our main cohort and the rest of the subgroups,” the researchers said.
“We do not believe these results should be interpreted as representing a truly protective effect of surgery,” they cautioned. “Rather, there is no increased rate of incident dementia in older adults undergoing elective noncardiac surgical procedures as compared with nonsurgical controls over a 5-year follow-up period.”
A limitation to the study is its retrospective design, the study authors noted. They also did not include detailed information on individuals' cognitive function prior to surgery. In addition, because less than half of all surgical patients in the database were successfully matched to a nonsurgical control, the results may not be generalizable to the entire surgical patient population.
Overall, findings “will help guide discussions around surgical decision-making and aid in informed decision-making around long-term cognitive outcomes in older adults considering elective surgical interventions,” the study authors said. Future research should examine rates of dementia in patients who have been exposed to surgery and anesthesia repeatedly or undergone other elective surgeries or urgent surgeries, they concluded.