Table 2.
All data | Clinic-only data | Bootstrap results |
|||
---|---|---|---|---|---|
Hazard ratio | p value | Hazard ratio | p value | p value | |
Sex | |||||
Male | 1 | Reference | 1 | Reference | |
Female | 1.07 | 0.52 | 1.16 | 0.46 | 0.50 |
Age | 1.12 | <0.001 | 1.14 | <0.001 | 0.040 |
Education | Omnibus: p<0.001 | Omnibus: p=0.32 | |||
≤12 years | 1 | Reference | 1 | Reference | |
13–16 years | 0.79 | 0.015 | 0.84 | 0.38 | 0.61 |
17+ years | 0.57 | <0.001 | 0.64 | 0.15 | 0.44 |
Race | |||||
Other | 1 | Reference | 1 | Reference | |
White | 0.83 | 0.26 | 1.00 | 0.99 | 0.35 |
Medical conditions | |||||
Diabetes | 1.16 | 0.40 | 1.76 | 0.09 | 0.039 |
Hypertension | 0.85 | 0.13 | 0.90 | 0.63 | 0.62 |
Heart | 1.03 | 0.81 | 1.36 | 0.24 | 0.09 |
Cerebrovascular disease | 1.29 | 0.13 | 2.42 | 0.002 | 0.006 |
APOE genotype | |||||
0 ε4 alleles | 1 | Reference | 1 | Reference | |
1 or more ε4 alleles | 1.66 | <0.001 | 2.28 | <0.001 | 0.008 |
Comorbidity | Omnibus: p=0.39 | Omnibus: p=0.55 | |||
RxRisk = 1 | 1 | Reference | 1 | Reference | |
RxRisk = 2 | 0.92 | 0.54 | 0.99 | 0.96 | 0.66 |
RxRisk = 3 | 0.96 | 0.78 | 0.69 | 0.20 | 0.034 |
RxRisk = 4 | 1.18 | 0.26 | 0.81 | 0.54 | 0.044 |
Bootstrap results give the probability that hazard ratios this different would be observed by chance alone. Each bootstrap sample is generated by randomly drawing individuals from the “all data” dataset with replacement until the same sample size as the “clinic only” dataset is reached. We then ran the same Cox model with that sample and kept track of its hazard ratio. We repeated this procedure 10,000 times, and ranked the hazard ratios. We compared the observed hazard ratio for the “clinic only” dataset to the bootstrapped hazard ratios to obtain the bootstrapped p values.