Table 1. Definitions of variables used in analyses to determine possible association between receipt of 2008–09 TIV and subsequent infection with influenza A(H1N1)pdm09 virus, Manitoba, Canada, 2009*†.
| Variable | Definition |
|---|---|
| Drugs‡ | |
| For HIV | Protease inhibitors (J05AE*), nucleoside and nucleotide reverse transcriptase inhibitors (J05AF*), nonnucleoside reverse transcriptase inhibitors (J05AG*), antivirals for treatment of HIV infections, combinations (J05AR*) |
| For influenza | Neuraminidase inhibitors (J05AH*) or cyclic amines (J05AC*) |
| For diabetes | Drugs used in diabetes (A10*), insulins and analogs (A10A*), blood glucose lowering drugs, excluding insulins (A10B*) |
| Immunosuppressants | Antineoplastic agents (L01*), immunosuppressants (L04A*) |
| Systemic antimicrobials | Antibacterials for systemic use (J01*), antimycotics for systemic use (J02*), antimycobacterials (J04*) |
| Systemic steroids | Corticosteroids for systemic use, plain (H02A*), glucocorticoids (H02AB*), corticosteroids for systemic use, combinations (H02B*) |
| Pregnancy§ | |
| Ongoing pregnancy | >1 admission code (O10–16, O20–29, O30–48, O94–99, Z32–36) or >2physician claims (640–649, V22) or >1 tariff code for prenatal services; must be within ±30 d of the index date (26) |
| Completion of pregnancy | >1 admission code (O8, O65–75, O80–84, O85–92, Z37–39) or >2 physician claims (650–659, 670–676) or >1 tariff code for delivery, abortion or postnatal services; must be within 270 d following the index date (26) |
| Medical condition§¶ | |
| Alcoholism | >1 admission (E24.4, E51.2, E52, F10, G31.2, G62.1, G72.1, I42.6, K29.2, K70, K86.0, O35.4, P04.3, Q86.0, R78.0, T50.6, T51.0, T51.1, T51.9, X45, X65, Y15, Y57.3, Y90, Y91, Z50.2, Z71.4, Z72.1, Z81.1) or >2 physician claims (291, 303) |
| Anemia | >1 admission (D50–64) or >2 physician claims (280–285) |
| Asthma | >1 admission (J45, J46) or >2 physician claims (493) |
| Cancer, excluding NMS | >1 admission (C00–43, C45–97) or >1 physician claim (140–172, 174–209, 235–239) |
| Cardiovascular disease | >1 admission (I00–99, O11) or >2 physician claims (390–519) |
| Chronic renal failure | >1 admission (I12.0, I13.1, N18, N19, N25.0, Z49, Z99.2) or >2 physician claims (403–404, 586–587) |
| Chronic respiratory condition | >1 admission (J40–99, O24) or >2 physician claims (490–496, 500–508) |
| COPD | >1 admission (J40–44, O24) or >2 physician claims (630–633, 634–639, 490–492, 496) |
| Diabetes | >1 admission (E10–14, G590, G632, H280, H360, M142, M146, N083, O24) or >2 physician claims (250) or >2 prescriptions for drugs used in treatment of diabetes |
| HIV/AIDS | >1 admission (B20–24, R75, Z21) or >2 physician claims (042 V08) or >1 prescriptions for drugs used in treatment of HIV |
| Hypertension | >1 admission (I10–15, I67.4, O11) >2 physician claims (401–405) |
| Immunodeficiency | >1 admission (D80–D84, D89) or >2 physician claims (288, 279) |
| Immunosuppressed | Having an organ transplant or a diagnosis of HIV/AIDS, other immunodeficiency disorders or cancer (other than nonmelanoma skin cancer), or receiving prescriptions for immunosuppressants or systemic steroids |
| Ischemic heart disease | >1 admission (I20–25) or >1 physician claims (410–414) |
| Organ transplant | >1 admission (T86, Y83.0, Z94) or >2 physician claims (V42) |
| Stroke | >1 admission (I61, I63, I64, I67.9, I69) or >2 physician claims (431, 434, 436–438) |
| Substance abuse | >1 admission (F11–16, F18–19) or >2 physician claims (292, 304,305) |
| Other | |
| Area of residence | Based on postal code of current address and the North-South relationship variable derived by using PCCF+#; North includes areas coded as “North” or "North transition"; South includes areas coded as "South" or "South transition" |
*Asterisks indicate a wild-card character used as an alternative to listing all disease or drug codes within a section or subsection of the corresponding classification system. †TIV, inactivated trivalent influenza vaccine; NMS, nonmelanoma skin cancer; COPD, chronic obstructive pulmonary disease. ‡Drugs were classified based according to their drug identification number and the Anatomical Therapeutic Chemical Classification System with Defined Daily Doses (www.who.int/classifications/atcddd/en/). §Codes in parentheses are International Classification of Diseases (ICD)-10-CA codes for hospital admission data and ICD-9-CM codes for physician claims data. ¶Based on previously validated chronic disease identification algorithms with modifications. #Automated Postal Code Conversion File Plus system, Statistics Canada (www.statcan.gc.ca/bsolc/olc-cel/olc-cel?lang=eng&catno=82F0086X).