Table 6.
Univariate and Multivariate Analyses of Household and Household Member Characteristics Associated With Secondary Cough Illnesses in the Household — Wisconsin, 1 October 2011–31 May 2012
| Univariate Analysis | |||
|---|---|---|---|
| Household Member had a Secondarya Cough Illness | |||
| Characteristic | No 101 Households With 300 Nonprimary Patient Household Members | Yes 19 Households With 61 Nonprimary Patient Household Members | P Valueb |
| Number of members in household aged <10 y, median (IQR) | 2 (1–2) | 2 (2–2) | .156 |
| Days household was followed, median (IQR) | 29 (18–46) | 32 (20–62) | .424 |
| Azithromycin treatment received by household primary patient, No.(%) | 84 (83) | 15 (79) | .742 |
| Days from cough onset to initiation of azithromycin treatment by household primary patient, median (IQR) | 7 (4–12) | 14 (8–15) | .046 |
| Azithromycin prophylaxis received by household members, No. (%) | 93 (31) | 12 (20) | .086 |
| Days from cough onset in household primary patient to initiation of azithromycin prophylaxis by household member, median (IQR) | 8 (6–13) | 15 (15–17) | <.001 |
| Multivariate Analysis | |||
| n (%) | n (%) | Adjustedc RR (95% CI) | |
| Azithromycin treatment of household primary patient | |||
| None | 17 (17) | 4 (21) | Reference |
| Initiated <1 wk after cough onset | 39 (39) | 3 (16) | 0.60 (.14–2.46) |
| Initiated ≥1 wk after cough onset | 45 (45) | 12 (63) | 1.31 (.46–3.70) |
| Azithromycin prophylaxis of individual household member | |||
| None | 211 (70) | 49 (80) | Reference |
| Initiated <2 wks after cough onset in household primary patient | 70 (23) | 2 (3) | 0.16 (.04–.69) |
| Initiated ≥2 wk after cough onset in household primary patient | 19 (6) | 10 (16) | 1.40 (.66–2.99) |
Abbreviations: CI, confidence interval; IQR, interquartile range; RR, relative risk.
Secondary cough illness is defined as cough onset in a household member 7–16 days after cough onset in the household primary patient.
P-value of χ2 test or Fisher exact test for categorical variables and Mann–Whitney U test for continuous variables.
Adjusted relative risk of secondary cough illness in the household, adjusted for azithromycin prophylaxis of household members, azithromycin treatment of household primary patients, and for repeated measurements within each household.