Background The American College of Surgeons and the American Geriatrics Society have suggested that preoperative cognitive screening should be performed in older surgical patients. We hypothesized that unrecognized cognitive impairment in patients without a history of dementia is a risk factor for development of postoperative complications. Methods We enrolled 211 patients 65 yr of age or older without a diagnosis of dementia who were scheduled for an elective hip or knee replacement. Patients were cognitively screened preoperatively using the Mini-Cog and demographic, medical, functional, and emotional/social data were gathered using standard instruments or review of the medical record. Outcomes included discharge to place other than home (primary outcome), delirium, in-hospital medical complications, hospital length-of-stay, 30-day emergency room visits, and mortality. Data were analyzed using univariate and multivariate analyses. Results Fifty of 211 (24%) patients screened positive for probable cognitive impairment (Mini-Cog less than or equal to 2). On age-adjusted multivariate analysis, patients with a Mini-Cog score less than or equal to 2 were more likely to be discharged to a place other than home (67% vs. 34%; odds ratio = 3.88, 95% CI = 1.58 to 9.55), develop postoperative delirium (21% vs. 7%; odds ratio = 4.52, 95% CI = 1.30 to 15.68), and have a longer hospital length of stay (hazard ratio = 0.63, 95% CI = 0.42 to 0.95) compared to those with a Mini-Cog score greater than 2. Conclusions Many older elective orthopedic surgical patients have probable cognitive impairment preoperatively. Such impairment is associated with development of delirium postoperatively, a longer hospital stay, and lower likelihood of going home upon hospital discharge.

Background Preexisting cognitive impairment is emerging as a predictor of poor postoperative outcomes in seniors. We hypothesized that preoperative cognitive screening can be performed in a busy preadmission evaluation center and that cognitive impairment is prevalent in elective geriatric surgical patients. Methods We approached 311 patients ≥ 65 years-old presenting for preoperative evaluation prior to elective surgery in a prospective, observational, single-center study. Forty-eight patients were ineligible and 63 declined. The remaining 200 were randomized to the Mini-Cog (N =100) or Clock-in-the-Box [CIB; N = 100)] test. Study staff administered the test in a quiet room and 2 investigators scored the tests independently. Probable cognitive impairment was defined as a Mini-Cog ≤ 2 or a CIB ≤ 5. Results The age of consenting patients was 73.7± 6.4 (mean ± SD) years. There were no significant differences between patients randomized to the Mini-Cog or CIB test in age, weight, gender, education, ASA physical status or Charlston Index. Overall, 23% of patients met criteria for probable cognitive impairment, and prevalence was virtually identical regardless of the test used; 22% screened with the Mini-Cog and 23% screened with the CIB scored as having probable cognitive impairment (P =1.0 by Chi Square analysis). Both tests had good inter-rater reliability (Krippendroff's alpha = 0.86 (0.72–0.93) for Mini-Cog and 1 (1-1) for CIB). Conclusions Preoperative cognitive screening is feasible in most geriatric elective surgical patients and reveals a substantial prevalence of probable cognitive impairment in this population.