Baseline characteristics of study cohort before and after PS matching
| All (n=187 897) | Before PS matching | After PS matching* | |||||
| Statin (n=25 447) | Non-statin (n=162 450) | ASD† | Statin (n=17 662) | Non-statin (n=30 304) | ASD† | ||
| Age at index colonoscopy (years) | 62.1±12.3 | 68.0±10.5 | 61.2±12.3 | 0.50 | 61.7±11.0 | 63.6±13.8 | 0.09 |
| Male sex (n, %) | 91 961 (48.9) | 13 319 (52.3) | 78 642 (48.4) | 0.05 | 8935 (50.6) | 15 024 (49.6) | 0.01 |
| History of colonic polyps (n, %) | 39 066 (20.8) | 6754 (26.5) | 32 312 (19.9) | 0.09 | 4344 (24.6) | 7530 (24.8) | 0.01 |
| Polypectomy at index colonoscopy (n, %) | 28 724 (15.3) | 3663 (14.4) | 25 061 (15.4) | 0.02 | 2519 (14.3) | 4875 (16.1) | 0.02 |
| Smoking (n, %) | 3874 (2.1) | 699 (2.7) | 3175 (2.0) | 0.06 | 450 (2.5) | 974 (2.6) | 0.02 |
| Alcohol (n, %) | 1065 (0.6) | 101 (0.4) | 964 (0.6) | 0.002 | 77 (0.4) | 127 (0.4) | 0.002 |
| DM (n, %) | 17 935 (9.5) | 7448 (29.3) | 10 487 (6.5) | 0.35 | 3486 (19.7) | 5684 (18.8) | 0.04 |
| Hypertension (n, %) | 28 982 (15.4) | 10 104 (39.7) | 28 982 (15.4) | 0.38 | 4968 (28.1) | 7925 (26.2) | 0.03 |
| Dyslipidaemia (n, %) | 9557 (5.1) | 6828 (26.8) | 9557 (5.1) | 0.28 | 1573 (8.9) | 1622 (5.4) | 0.05 |
| AF (n, %) | 5673 (3.0) | 1712 (6.7) | 3961 (2.4) | 0.15 | 1030 (5.8) | 1833 (6.0) | 0.03 |
| IHD (n, %) | 13 266 (7.1) | 8094 (31.8) | 5172 (3.2) | 0.40 | 2919 (16.5) | 3203 (10.6) | 0.06 |
| CHF (n, %) | 6302 (3.4) | 2442 (9.6) | 3860 (2.4) | 0.18 | 1163 (6.6) | 1777 (5.9) | 0.01 |
| Stroke (n, %) | 7638 (4.1) | 3385 (13.3) | 4253 (2.6) | 0.28 | 1591 (9.0) | 2461 (8.1) | 0.02 |
| CRF (n, %) | 3924 (2.1) | 1718 (6.8) | 2206 (1.4) | 0.15 | 753 (4.3) | 1174 (3.9) | 0.01 |
| Cirrhosis (n, %) | 1250 (0.7) | 113 (0.4) | 1137 (0.7) | 0.23 | 82 (0.5) | 149 (0.5) | 0.006 |
| Dementia (n, %) | 1258 (0.7) | 269 (1.1) | 989 (0.6) | 0.05 | 173 (1.0) | 322 (1.1) | 0.02 |
| Parkinsonism (n, %) | 779 (0.4) | 129 (0.5) | 650 (0.4) | 0.02 | 82 (0.5) | 160 (0.5) | 0.01 |
| Aspirin (n, %) | 28 569 (15.2) | 14 224 (55.9) | 14 345 (8.8) | 0.68 | 7181 (40.7) | 10 838 (35.8) | 0.02 |
| NSAIDs (n, %) | 21 757 (11.6) | 3786 (14.9) | 17 971 (11.1) | 0.85 | 2574 (14.6) | 4595 (15.2) | 0.02 |
| COX-2 inhibitors (n,%) | 378 (0.2) | 86 (0.3) | 292 (0.2) | 0.02 | 52 (0.3) | 127 (0.4) | 0.02 |
| Centre endoscopy volume | 2683±953 | 2712±988 | 2678±947 | 0.04 | 2704±986 | 2717±961 | <0.001 |
| Centre polypectomy rate | 24.9%±4.5% | 25.7%±4.3% | 24.8%±4.5% | 0.05 | 25.5±4.3% | 25.5±4.4% | 0.004 |
Continuous variables were expressed as mean (years)±1 SD.
Categorical variables were expressed as number (%).
Drug use was defined as use for more than 90 days and expressed as number (%).
*PS matching was performed after trimming of the extreme PS strata (5th and 95th percentiles). Non-statin users were matched to statin users on PS within a calliper width of 0.1. All variables were included in the model for PS estimation.
†Variables with an ASD >0.20 is considered to be imbalanced.
AF, atrial fibrillation; ASD, absolute standardised difference; CHF, congestive heart failure; COX-2, cyclooxygenase-2; CRF, chronic renal failure; DM, diabetes mellitus; IHD, ischaemic heart disease; NSAIDs, non-steroidal anti-inflammatory drugs; PS, propensity score.