Table 2. Multivariable analysis of index episode risk factors for subsequent smear-positive tuberculosis re-treatment (N = 1,733).

	Total re-treatment cases	PY	Rate (per 100 PY)	Crude hazard-ratio* (95% CI)	P-value
Treatment outcome					<0.001
Cured	185	8863	2.09 (1.81–2.41)	1
Completed	14	640	2.19 (1.29–3.69)	1.08 (0.58–2.00)
Defaulted	92	1341	6.86 (5.59–8.41)	3.97 (3.00–5.26)
Smear grade †					0.03‡
Smear 1+	35	1588	2.20 (1.58–3.07)	1
Smear 2+	48	1576	3.05 (2.30–4.04)	1.43 (0.93–2.22)
Smear 3+	154	4641	3.32 (2.83–3.89)	1.61 (1.11–2.33)
Age					0.003
0–18	30	758	3.96 (2.77–5.66)	1
19–39	193	6646	2.90 (2.52–3.34)	0.50 (0.32–0.78)
40+	68	3430	1.98 (1.56–2.51)	0.40 (0.25–0.65)

PY = Person-years.

CI = Confidence Interval.

^*Adjusted for the other factors shown in the table.

^†Smear grade at start of treatment:

Smear 3+: Any of the two initial smears was 3+, i.e. >10 acid-fast bacilli (AFB) per 1 high-power field (HPF).

Smear 2+: Any of the two initial smears was 2+, i.e. 1–10 AFB per 1 HPF, but none of them was 3+.

Smear 1+: Any of the two initial smears was 1+, i.e. 10–99 AFB per 100 HPF, but none of them was 2+ or 3+.

^‡Test for trend.