Table 4. Cox proportional hazard regression analysis of potential independent variables associated with time to recurrence of Clostridium difficile infections, Hong Kong, China, 2006–2014*.
| Variable | Univariate analysis |
Multivariate analysis |
||||
|---|---|---|---|---|---|---|
| β | Hazard ratio (95% CI) | p value | β | Adjusted hazard ratio (95% CI) | p value | |
| Age, y | ||||||
| <44 | NA | 1.0 | NA | NA | 1.0 | NA |
| 45−64 | 0.14 | 1.15 (0.86–1.55) | 0.34 | 0.01 | 1.00 (0.74–1.36) | 0.99 |
| 65−84 | 0.29 | 1.33 (0.01–1.75) | 0.04 | 0.04 | 1.04 (0.78–1.38) | 0.81 |
| >85 | 0.41 | 1.50 (1.14–1.98) | <0.01 | 0.16 | 1.17 (0.87–1.56) | 0.29 |
| Male sex | −0.02 | 0.99 (0.88–1.10) | 0.79 | NA | NA | NA |
| Resident of home for elderly persons | −0.02 | 0.98 (0.87–1.11) | 0.99 | NA | NA | NA |
| Severe disease† | 0.32 | 1.38 (1.22–1.55) | <0.01 | 0.35 | 1.41 (1.26–1.59) | <0.01 |
| Antimicrobial drug use‡ | ||||||
| High-risk drug | 0.49 | 1.55 (1.36–1.77) | <0.01 | 0.32 | 1.37 (1.20–1.57) | <0.01 |
| Medium-risk drug | 0.41 | 1.51 (1.33–1.72) | 0.01 | −0.01 | 0.99 (0.86–1.16) | 0.96 |
| Low-risk drug | 0.11 | 1.12 (0.69–1.83) | 0.66 | NA | NA | NA |
| Diagnostic test | ||||||
| Bacterial culture | NA | 1.0 | NA | NA | 1.0 | NA |
| Toxin detection | 0.69 | 1.89 (1.62–2.21) | 0.01 | 0.57 | 1.79 (1.53–2.11) | <0.01 |
| NAAT | 0.27 | 1.31 (1.12–1.52) | 0.01 | 0.23 | 1.26 (1.08–1.47) | <0.01 |
| Use of proton-pump inhibitor | 0.08 | 1.09 (0.97–1.22) | 0.16 | NA | NA | NA |
| Use of histamine-2 receptor antagonist | 0.18 | 1.19 (1.07–1.34) | 0.01 | 0.09 | 1.09 (0.97–1.22) | 0.15 |
| Healthcare-associated disease | 0.49 | 1.65 (1.15–2.35) | 0.01 | 0.42 | 1.52 (1.06–2.20) | 0.02 |
| Concurrent condition | ||||||
| Myocardial infarction | 0.09 | 1.10 (0.92–1.32) | 0.32 | NA | NA | NA |
| Cerebrovascular disease | 0.49 | 1.63 (1.46–1.82) | <0.01 | −0.15 | 0.86 (0.74–0.99) | 0.04 |
| Chronic lung disease | −0.05 | 0.95 (0.82–1.12) | 0.56 | NA | NA | NA |
| Diabetes mellitus | 0.08 | 1.08 (0.94–1.24) | 0.30 | NA | NA | NA |
| Renal disease | 0.05 | 1.05 (0.92–1.20) | 0.47 | NA | NA | NA |
| Nonmetastatic tumor | −0.24 | 0.79 (0.69–0.90) | 0.01 | −0.15 | 0.86 (0.74–0.99) | 0.04 |
| AIDS | −0.58 | 0.56 (0.18–1.74) | 0.32 | NA | NA | NA |
| Inflammatory bowel disease | 0.14 | 1.15 (0.62–2.14) | 0.66 | NA | NA | NA |
*NA, not applicable; NAAT, nucleic acid amplification test. †Severe disease was diagnosed according to the according to criteria of Cohen et al (13). ‡Antimicrobial drug use 8 weeks before diagnosis was stratified into high risk (floroquinolones, cephalosporins, and clindamycin); medium risk (penicillins, macrolides, and sulfonamides); and low risk (tetracyclines).