Table 3. Rate ratio (RR) of recurrent subdural haematoma (SDH) in surgically- and conservatively treated patients, according to potential predictors in Denmark 1996–2011.
| Potential predictors for recurrent SDH | Surgical treatment | Conservative treatment | P-value + | ||||
|---|---|---|---|---|---|---|---|
| Events | Adjusted RR ** | (95% CI*) | Events | Adjusted RR ** | (95% CI*) | ||
| Age (years) | |||||||
| 20–49 | 123 | 1 | (Ref.) | 132 | 1 | (Ref.) | 0.005 |
| 50–69 | 317 | 0.90 | (0.73–1.12) | 194 | 1.29 | (1.04–1.62) | |
| 70- | 517 | 1.12 | (0.91–1.38) | 272 | 1.79 | (1.44–2.23) | |
| Gender | |||||||
| Males | 743 | 1.69 | (1.45–1.97) | 414 | 1.50 | (1.26–1.79) | 0.31 |
| Females | 214 | 1 | (Ref.) | 184 | 1 | (Ref.) | |
| Alcohol addiction | |||||||
| Yes | 186 | 1.29 | (1.08–1.53) | 150 | 1.10 | (0.90–1.33) | 0.20 |
| No | 771 | 1 | (Ref.) | 448 | 1 | (Ref.) | |
| Chronic liver disease | |||||||
| Yes | 43 | 1.35 | (0.96–1.83) | 32 | 1.19 | (0.81–1.68) | 0.60 |
| No | 914 | 1 | (Ref.) | 566 | 1 | (Ref.) | |
| Coagulopathy | |||||||
| Yes | 6 | 0.70 | (0.28–1.42) | 9 | 2.24 | (1.07–4.10) | 0.03 |
| No | 951 | 1 | (Ref.) | 589 | 1 | (Ref.) | |
| Renal insufficiency | |||||||
| Yes | 18 | 0.92 | (0.56–1.43) | 18 | 1.65 | (0.99–2.56) | 0.09 |
| No | 939 | 1 | (Ref.) | 580 | 1 | (Ref.) | |
| Diabetes mellitus | |||||||
| Yes | 53 | 1.24 | (0.92–1.64) | 40 | 1.67 | (1.18–2.29) | 0.18 |
| No | 904 | 1 | (Ref.) | 558 | 1 | (Ref.) | |
| Previous cerebral ischemic infarction | |||||||
| Yes | 60 | 0.86 | (0.66–1.11) | 53 | 1.25 | (0.93–1.64) | 0.07 |
| No | 897 | 1 | (Ref.) | 545 | 1 | (Ref.) | |
| Statins | |||||||
| Yes | 112 | 1.00 | (0.81–1.24) | 60 | 0.93 | (0.69–1.22) | 0.64 |
| No | 845 | 1 | (Ref.) | 538 | 1 | (Ref.) | |
| Trauma diagnosis † | |||||||
| Yes | 531 | 1.19 | (1.04–1.36) | 396 | 1.06 | (0.89–1.26) | 0.30 |
| No | 426 | 1 | (Ref.) | 202 | 1 | (Ref.) | |
| PDMD †† | |||||||
| Yes | 17 | 1.11 | (0.66–1.74) | 13 | 0.98 | (0.53–1.63) | 0.74 |
| No | 940 | 1 | (Ref.) | 585 | 1 | (Ref.) | |
* 95% Confidence interval
** Rate ratios adjusted for age, gender, calendar period, time since admittance for first SDH, length of hospital stay for the primary SDH, and the potential predictors for recurrent SDH listed in Table 1.
+ P-value: test for similar RR’s for surgically vs conservatively treated patients for each predictive factor.
† Trauma diagnosis less than 2 years before the primary SDH
†† PDMD: Pre-packaged Daily Medication Doses.