Table 1. Comparison of conventionally and BED-estimated incidence in two cohorts.

Time Period	PY	No. at risk	Estimated No. of incident infections		Annualized incidence/100 PY
			Conventional	BED	Conventional (CI)	BED (CI)
Thailand military conscript cohort
Months
5	324	867	2	2.0	0.62 (0.00–1.48)	1.49 (0.00–3.57)
17	660	662	9	9.5	1.38 (0.47–2.29)	1.48 (0.02–2.93)
23	207	472	3	1.2	1.47 (0.00–3.15)	1.18 (0.00–3.49)
Subtotal	1191		14	12.7	1.19 (0.56–1.82)	1.43(0.36–2.49)
BMA injection drug user cohort
Months
8	709	942	52	34	7.91 (5.68–10.15)	5.22 (4.65–9.87)
16	620	805	38	34	6.53 (4.39–8.67)	5.85 (0.48–11.22)
24	515	668	30	28	6.19 (3.90–8.47)	5.77 (0.00–14.43)
Subtotal	1844		120	96	6.96 (5.67–8.25)	5.49 (2.22–8.76)

PY, person-years; CI, 95% confidence interval; BMA, Bangkok Metropolitan authority.