Of the 2,346 patients with hip fractures, 150 (6.4%) patients were diagnosed with dementia. The 30-day, 60-day, 3-month, 6-month, and 1-year postoperative cumulative mortality rates were 1.8%, 3.8%, 5.6%, 8.9%, and 13.6%, respectively, in the non-dementia group, and 2%, 7.3%, 14%, 19.3%, and 24%, respectively, in the dementia group (
Table 1,
Fig. 2). The dementia group was older (
P = 0.010), had a higher proportion of women (
P = 0.034), worse CCI (
P < 0.001), and higher prevalence of general anesthesia (
P = 0.001).
To analyze the risk factors for the 30-day, 60-day, 3-month, 6-month, and 1-year mortality in elderly patients with hip fractures, multivariable logistic regression was performed (
Table 2). Age (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.03–1.12;
P < 0.001) was identified as a factor that affected the 30-day mortality, and age (OR, 1.07; 95% CI, 1.04–1.10;
P < 0.001), sex (OR, 2.64; 95% CI, 1.71–4.07;
P < 0.001), CCI (OR, 1.28; 95% CI, 1.10–1.48;
P = 0.001), and dementia (OR, 1.68; 95% CI, 1.34–2.35;
P < 0.001) were identified as factors that affected the 60-day mortality. The factors that affected the 3-month mortality were age (OR, 1.08; 95% CI, 1.05–1.10;
P < 0.001), sex (OR, 2.19; 95% CI, 1.51–3.16;
P < 0.001), CCI (OR, 1.25; 95% CI, 1.10–1.42;
P = 0.001), and dementia (OR, 1.48; 95% CI, 1.28–1.81;
P = 0.006). The factors that affected the 6-month mortality were age (OR, 1.07; 95% CI, 1.05–1.09;
P < 0.001), sex (OR, 2.25; 95% CI, 1.66–3.04;
P < 0.001), CCI (OR, 1.28; 95% CI, 1.16–1.42;
P < 0.001), and dementia (OR, 1.54; 95% CI, 1.34–1.86;
P = 0.009). The factors that affected the 1-year mortality were age (OR, 1.06; 95% CI, 1.02–1.08;
P < 0.001), sex (OR, 2.68; 95% CI, 2.07–3.47;
P < 0.001), CCI (OR, 1.34; 95% CI, 1.23–1.47;
P < 0.001), and dementia (OR, 1.70; 95% CI, 1.46–1.08;
P = 0.016).
In the subgroup analysis, among the 150 patients with dementia, the 30-day and 60-day, 3-month, 6-month, and 1-year postoperative cumulative mortality rates were 1.1%, 4.5%, 9.1%, 12.1%, and 15.2%, respectively, in the no-medication subgroup (66 patients), and 2.4%, 9.5%, 17.9%, 19.3%, and 31%, respectively, in the medication subgroup (84 patients) (
Table 3,
Fig. 2).