Table 3.
Associations between cancer survivorship covariates, and time to statin cessation among statin initiators
| Statin initiators | Number of eventsa | Person-Years of Follow-Up (hundreds) | Crude Rate (per 100 Person-Years) | Unadjusted HRb | p-value | Adjusted HRc | p-value | ||
|---|---|---|---|---|---|---|---|---|---|
| n | % | ||||||||
| Cancer status (binary) | |||||||||
| Non-cancer | 354,961 | 96.8 | 183,844 | 92.5 | 19.8 | 1 | 0.502 | 1 | 0.02 |
| Cancer survivor | 11,810 | 3.2 | 5962 | 2.8 | 20.7 | 1.02 (0.96–1.09) | 1.07 (1.01–1.12) | ||
| Sex | |||||||||
| Males | 193,646 | 52.8 | 98,246 | 50.6 | 19.4 | 1 | < 0.001 | 1 | < 0.001 |
| Females | 173,125 | 47.2 | 91,560 | 44.7 | 20.5 | 1.05 (1.04–1.06) | 1.05 (1.04–1.06) | ||
| Age (yrs) | |||||||||
| 40–49 | 44,088 | 12.0 | 26,453 | 9.8 | 27.1 | 1 | < 0.001 | 1 | < 0.001 |
| 50–59 | 95,539 | 26.1 | 51,099 | 24.5 | 20.8 | 0.81 (0.80–0.82) | 0.80 (0.79–0.82) | ||
| 60–69 | 126,570 | 34.5 | 60,763 | 34.9 | 17.4 | 0.69 (0.68–0.70) | 0.66 (0.65–0.67) | ||
| 70–79 | 75,425 | 20.6 | 37,647 | 20.5 | 18.4 | 0.73 (0.71–0.75) | 0.68 (0.67–0.70) | ||
| 80+ | 25,149 | 6.9 | 13,844 | 5.7 | 24.2 | 0.89 (0.85–0.93) | 1.14 (1.05–1.24) | ||
| BMI (kg/m2) | |||||||||
| < 18.5 | 3035 | 0.8 | 1773 | 0.6 | 28.9 | 1.25 (1.20–1.30) | < 0.001 | 1.18 (1.14–1.23) | < 0.001 |
| 18.5–25 | 90,123 | 24.6 | 48,251 | 22.6 | 21.3 | 1 | 1 | ||
| ≥ 25 | 273,613 | 74.6 | 139,782 | 72.1 | 19.4 | 0.92 (0.91–0.93) | 0.94 (0.93–0.95) | ||
| Cholesterol (mmol/L) | |||||||||
| Normal (< 5) | 59,402 | 16.2 | 29,003 | 15.8 | 18.4 | 1 | < 0.001 | ||
| Mod-High (5–8) | 279,538 | 76.2 | 146,489 | 72.4 | 20.2 | 1.10 (1.09–1.11) | |||
| High (> 8) | 24,778 | 6.8 | 12,533 | 6.8 | 18.5 | 1.01 (0.99–1.03) | |||
| Missing | 3053 | 0.8 | |||||||
| Smoking status | |||||||||
| Never smoker | 117,658 | 32.1 | 61,055 | 31.1 | 19.6 | 1 | < 0.001 | 1 | < 0.001 |
| Ex-smoker | 169,393 | 46.2 | 84,172 | 45.3 | 18.6 | 0.94 (0.93–0.96) | 0.98 (0.96–0.99) | ||
| Current smoker | 79,720 | 21.7 | 44,579 | 19.0 | 23.5 | 1.16 (1.14–1.17) | 1.13 (1.12–1.15) | ||
| Alcohol status | |||||||||
| Non-drinker | 76,637 | 20.9 | 40,349 | 20.0 | 20.2 | 1 | < 0.001 | ||
| Ex-drinker | 13,239 | 3.6 | 6783 | 3.6 | 18.9 | 0.95 (0.92–0.97) | |||
| Current drinker | |||||||||
| light | 143,351 | 39.1 | 72,291 | 39.2 | 18.4 | 0.93 (0.90–0.95) | |||
| moderate | 16,097 | 4.4 | 8198 | 4.3 | 18.9 | 0.95 (0.91–0.99) | |||
| heavy | 19,720 | 5.4 | 10,777 | 4.7 | 22.8 | 1.09 (1.07–1.12) | |||
| amount unknown | 10,869 | 3.0 | 5772 | 2.8 | 20.3 | 1.01 (0.96–1.05) | |||
| Missing | 86,858 | 23.7 | |||||||
| Medical history | |||||||||
| Diabetes | 70,990 | 19.4 | 34,520 | 19.9 | 17.3 | 0.87 (0.85–0.88) | < 0.001 | 0.83 (0.82–0.84) | < 0.001 |
| Chronic kidney disease | 25,278 | 6.9 | 12,243 | 5.7 | 21.4 | 1.01 (0.98–1.05) | < 0.001 | ||
| Chronic liver disease | 6440 | 1.8 | 3395 | 1.4 | 23.5 | 1.12 (1.08–1.16) | < 0.001 | ||
| IMD quintile | |||||||||
| 1 (least deprived) | 40,769 | 11.1 | 21,052 | 11.7 | 18.0 | 1 | < 0.001 | ||
| 2 | 43,256 | 11.8 | 22,097 | 11.9 | 18.6 | 1.01 (0.97–1.06) | |||
| 3 | 48,504 | 13.2 | 24,908 | 13.1 | 19.1 | 1.03 (0.98–1.09) | |||
| 4 | 187,806 | 51.2 | 98,030 | 46.1 | 21.3 | 1.11 (1.06–1.17) | |||
| 5 (most deprived) | 46,436 | 12.7 | 23,719 | 12.6 | 18.8 | 1.03 (0.97–1.09) | |||
| Calendar year | |||||||||
| 2005–07 | 155,758 | 42.5 | 86,412 | 56.6 | 15.3 | 1 | < 0.001 | ||
| 2008–10 | 124,788 | 34.0 | 67,538 | 30.1 | 22.5 | 1.27 (1.26–1.29) | |||
| 2011–13 | 86,225 | 23.5 | 35,856 | 8.7 | 41.3 | 1.52 (1.50–1.55) | |||
aEvents = first cessation of statin therapy defined as a no further prescriptions 90 days after the expected end date of the last prescription
bCox model with time since study entry (i.e. statin initiation) as the timescale
cAdjusted for a priori confounders [age (time-updated), gender, body mass index, smoking status and diabetes (time-updated)]. No other covariates changed the association between cancer survivorship and statin cessation by more than 10%.
All regression models are restricted to patients with complete data for a-priori confounders