Table 1. “True” acute poisoning admissions, by age and sex, and systematic bias observed in estimates obtained through three possible hospital admission data sets, Anuradhapura district, Sri Lanka, September 2008 to January 2010.

Group	No. of “true” total admissionsa		All admissions to primary hospitals onlyb						All admissions to referral hospital onlyc						All admissionsd
			No.		Absolute difference		Per cent difference (bias)		No.		Absolute difference		Per cent difference (bias)		No.		Absolute difference		Per cent difference (bias)
Age (years)e
12−14	120		97		23		19.2		94		26		21.7		191		71		59.2
15−19	980		811		169		17.2		739		241		24.6		1550		570		58.3
20−29	1364		1081		283		20.7		1098		266		19.5		2179		815		59.8
30−39	607		489		118		19.4		496		111		18.3		985		378		62.3
40−49	416		351		65		15.6		325		91		21.9		676		260		62.5
50−59	210		182		28		13.3		152		58		27.6		334		124		59.0
≥ 60	95		79		16		16.8		71		24		25.3		150		55		58.0
Total	3792		3090		702		18.5		2976		816		21.7		6066		2274		60.0
Sex
Females	1952		1578		374		19.2		1512		440		22.5		3090		1138		58.3
Males	1861		1533		328		17.6		1477		384		20.6		3010		1149		61.7
Poisoning type
All pesticides	1573		1352		221		14.0		1293		280		17.8		2989		1416		90.0
Medicine overdose	789		561		228		28.9		627		162		20.5		1188		399		50.6
Other poison	1451		1198		253		17.4		1060		391		26.9		2258		807		55.6
Total	3813		3111		702		18.5		2974		817		21.6		6063		2272		59.9

^a Sum of all direct acute poisoning admissions to the district’s primary hospitals and its referral hospital (i.e. all admissions minus transfers).

^b All admissions to primary hospitals only (all are direct admissions, not referrals).

^c All admissions (both direct and transfers) to the referral hospital.

^d Raw total of all admissions to all hospitals in the district (routine method used for government statistics, which double counts patients transferred to referral hospitals).

^e No age was recorded for 21 patients.