Table.
Risk for SOREs, by Number of Postpartum Prescriptions and Stratified by Delivery Type
| Outcome, by Delivery Type | No Prescription | 1 Prescription | 2 Prescriptions | ≥3 Prescriptions |
|---|---|---|---|---|
| All births, n (%) | 65 331 (31.2) | 112 951 (54.0) | 22 676 (10.8) | 8257 (4.0) |
| SORE, n | 613 | 1780 | 1182 | 1007 |
| Rate per 1000 PYs (95% CI) | 11.3 (10.5–12.3) | 19.7 (18.8–20.7) | 66.5 (62.8–70.3) | 160.0 (150.4–170.2) |
| Adjusted HR (95% CI)* | Reference | 1.4 (1.3–1.6) | 3.6 (3.2–4.0) | 7.0 (6.3–7.9) |
| SORE (excluding persistent opioid prescriptions), n | 289 | 671 | 278 | 178 |
| Rate per 1000 PYs (95% CI) | 5.3 (4.8–6.0) | 7.4 (6.9–8.0) | 15.6 (13.9–17.6) | 28.3 (24.4–32.8) |
| Adjusted HR (95% CI)* | Reference | 1.1 (0.9–1.3) | 1.6 (1.3–2.0) | 2.7 (2.1–3.4) |
| Vaginal births, n (%) | 59 392 (41.1) | 70 122 (48.5) | 11 411 (7.9) | 3763 (2.6) |
| SORE, n | 540 | 1217 | 694 | 522 |
| Rate per 1000 PYs (95% CI) | 11.0 (10.1–11.9) | 21.8 (20.6–23.1) | 78.1 (72.5–84.1) | 181.7 (167.1–197.6) |
| Adjusted HR (95% CI) | Reference | 1.5 (1.3–1.7) | 3.7 (3.3–4.2) | 7.2 (6.3–8.2) |
| SORE (excluding persistent opioid prescriptions), n | 246 | 455 | 164 | 98 |
| Rate per 1000 PYs (95% CI) | 5.0 (4.4–5.7) | 8.1 (7.4–8.9) | 18.4 (15.8–21.5) | 34.4 (28.2–41.9) |
| Adjusted HR (95% CI)* | Reference | 1.1 (0.9–1.3) | 1.8 (1.5–2.2) | 2.9 (2.3–3.8) |
| Cesarean births, n (%) | 5939 (9.2) | 42 829 (66.4) | 11 265 (17.5) | 4494 (7.0) |
| SORE, n | 73 | 563 | 488 | 485 |
| Rate per 1000 PYs (95% CI) | 15.2 (12.1–19.1) | 16.4 (15.1–17.8) | 54.8 (50.2–59.9) | 140.9 (128.9–154.0) |
| Adjusted HR (95% CI) | Reference | 1.2 (0.9–1.5) | 2.9 (2.2–3.6) | 5.9 (4.6–7.6) |
| SORE (excluding persistent opioid prescriptions), n | 43 | 216 | 114 | 80 |
| Rate per 1000 PYs (95% CI) | 8.9 (6.6–12.0) | 6.3 (5.5–7.2) | 12.8 (10.7–15.4) | 23.2 (18.7–28.9) |
| Adjusted HR (95% CI)* | Reference | 0.7 (0.5–1.0) | 1.0 (0.7–1.4) | 1.5 (1.03–2.5) |
| Sensitivity analyses (all births)† | ||||
| Including nonopioid deaths in outcome | Reference | 1.4 (1.2–1.6) | 3.5 (3.2–3.9) | 6.9 (6.2–7.7) |
| Excluding women who filled single opioid prescription during pregnancy | Reference | 1.5 (1.3–1.7) | 3.7 (3.3–4.2) | 7.6 (6.7–8.7) |
| Excluding complicated births | Reference | 1.6 (1.4–1.8) | 3.8 (3.4–4.4) | 8.0 (7.0–9.2) |
| Excluding women without enrollment for 1 y before birth | Reference | 1.5 (1.3–1.8) | 3.1 (2.6–3.7) | 6.1 (5.0–7.4) |
HR = hazard ratio; PY = person-year; SORE = serious opioid-related event.
Adjusted estimates were obtained from Cox regression models that adjusted for age, parity, income, distance to the birth hospital, race, ethnicity, tobacco use, rurality, Tennessee region, delivery year, severe maternal morbidity, perineal lacerations, bilateral tubal ligation, filling 1 opioid prescription during pregnancy, and conditions precluding nonsteroidal anti-inflammatory drug use (e.g., chronic kidney disease). Models also adjusted for mental health medications, mental health conditions, pain-related diagnoses, and procedures; these conditions were measured during both the antepartum and postpartum periods. To impute missing data for age, parity, income, and distance to the birth hospital, we used multiple imputation by chained equations and 10 imputed data sets (mi impute command in Stata). We assessed the fulfillment of the proportional hazards assumption through examination of Schoenfeld residuals and log-log plots.
Five sensitivity analyses were performed for the following scenarios: including 91 nonopioid deaths in the composite outcome, excluding 3166 women with persistent opioid use from the primary outcome, excluding women who filled a single opioid prescription during pregnancy (total n = 180 959), excluding complicated births (n = 165 640), and excluding women without enrollment for 1 year before birth (n = 103 335). The data presented are HRs and 95% CIs.