Appendix 1.
Comorbidities with ICD-CM codes for predicting SMM and non-transfusion SMM in administrative data.
| Comorbidity | ICD-9-CM | ICD-10-CM |
|---|---|---|
| Anemia, preexistinga | 280.0, 280.1, 280.9, 285.9, 280.8, 281, 282.0, 282.1, 282.3, 282.40, 282.41, 282.43, 282.44, 282.45, 282.46, 282.47, 282.49, 282.5, 282.60, 282.61, 282.63, 282.68, 282.7, 282.8, 282.9, 284, 285, 648.20, 648.21, 648.22, 628.23 | O99.01, O99.02, D50, D55, D56, D58, D59, D57.1, D57.20, D57.3, D57.40, D57.80 |
| Asthma, acute or moderate-severe | 493 | O99.5, J45.21, J45.22, J45.31, J45.32, J45.4, J45.5, J45.901, J45.902 |
| Bleeding disorder, preexistingc | 286.0–286.5, 286.7 287 | D66, D67, D68.0-D68.6, D69 |
| BMI (kg/m2) at delivery 40 or greaterd | Birth certificate - use code 278.01 if birth certificate not available | Birth certificate – use Z68.4, E66.01, E66.2 if birth certificate not available |
| Cardiac disease, preexisting | 394–397, 402–405, 412–414, 416.2, 416.8, 416.9, 428.22, 428.23, 428.32, 428.33, 428.42, 428.43, 745, 746, 648.5, 648.60648.63, 426, 427.0–427.4, 427.6–427.9 | I05-I09, I11-I13, I15, I16, I20, I25, I27.8, I30-I41, I44-I49, I50.22, I50.23, I50.32, I50.33, I50.42, I50.43, I50.812, I50.813 O99.41, O99.42, Q20-Q24 |
| Chronic hypertension | 401–405, 642.0–642.2, 642.7 | O10, O11, I10 |
| Chronic renal disease | 581–583, 585, 587, 588, 753, 250.4 249.4, 710.0 | O26.83, I12, I13, N03-N05, N07, N08, N11.1, N11.8, N11.9, N18, N25.0, N25.1, N25.81, N25.89, N25.9, N26.9 |
| Connective tissue or autoimmune disease | 710, 714, 279.4 | M30-M36 |
| Gastrointestinal diseasee | 539, 555–558, 570–579, 564, 646.7 | K50-K52, K70-K77, K80-K83, K85-K87, K94, K95, O26.6 |
| Gestational diabetes mellitus | 648.8 | O24.4 |
| HIV or AIDS | 042, V08 | O98.7, B20 |
| Major mental health disorderf | 295–298, 300.0, 300.21, 300.22, 300.3, 300.4, 301, 309 | F06, F20-F25, F28-F34, F39, F40.0, F41, F43, F53, F60 |
| Maternal age 35 y or older | Birth certificate/Discharge record | Birth certificate/Discharge record |
| Neuromuscular diseaseg | 345, 358 | G40, G70 |
| Placental abruption | 641.2 | O45 |
| Placenta accreta spectrumh | Use algorithm: no uterine rupture (665.0, 665.10, 665.11) PLUS (placenta previa (641.0, 641.1) or retained placenta (666.0, 667.x)) PLUS hysterectomy (PR 68.3–68.9) | O43.213, O43.223, O43.233 |
| Placenta previa, complete or partial | 641.01, 641.11 | O44.03, O44.13, O44.23, O44.33 |
| Preeclampsia with severe features | 642.5 | O14.1, O14.2, O11 |
| Preeclampsia without severe features or gestational hypertension | 642.3, 642.4, 642.7 | O13, O14.0, O14.9 |
| Preexisting diabetes mellitus | 250, 648.0 | E08-E13, O24.0, O24.1, O24.3, O24.8, O24.9, Z79.4 |
| Preterm birth (less than 37 wk) | Birth certificate (644.21 if not available) | Z3A.20-Z3A.36 |
| Previous cesarean birth | 654.2 | O34.21 |
| Pulmonary hypertension | 416.0, 416.8, 416.9 | I27.0, I27.2 |
| Substance use disorder | 291, 303, 304, 305, 648.30, 648.31, 648.32, 648.33 | F10-F19, O99.31, O99.32 |
| Thyrotoxicosis | 242 | E05 |
| Twin or multiple pregnancy | 651, V27.2-V27.7 | O30, O31, Z37.2-Z37.7 |
| Uterine fibroidsb | 218, 654.1 | D25, O34.1 |
All parent codes subsume child codes (e.g., 493 means 493.xx)
Revised from Leonard et al.8 to restrict to present on admission codes
Revised to include these two comorbidities, which were statistically significant in variable importance analyses for SMM.
Revised to exclude D68.8, D68.9 (could indicate DIC, an SMM indicator) and to restrict to present on admission codes.
Revised to include E66.01, E66.2 (severe obesity)
Revised to exclude O99.6, K00-K46, K55-K68, K80-K84, K90-K92 (found to be capturing non-relevant gastrointestinal diseases)
Revised to exclude O99.34 and include F06, F40.0, F41, F43, F53, F60 (revised codes to follow Veteran’s Administration recommendations for ICD-9-CM and ICD-10-CM coding of psychotic disorders, mood disorders, personality disorders, post-traumatic stress disorder, adjustment reactions, generalized anxiety, and panic disorders.41 Generalized anxiety and panic disorders conferred similar risk of the outcomes as the other disorders.)
Revised to exclude O99.35
Codes are PAS are not available in ICD-9-CM. Therefore, the ICD-9-CM algorithm follows the approach developed by Creanga et al.42 to identify PAS using ICD-9-CM. We found the PAS rate to be approximately 2 per 10,000 with that approach, and 11 per 10,000 with the ICD-10-CM approach in their respective time groups. Also revised from Leonard et al.8 to include only PAS if indicated in the third trimester