Syndromic surveillance for influenza in two hospital emergency departments. Relationships between ICD-10 codes and notified cases, before and during a pandemic

Table 6 Top correlations calculated between ICD-10 coded cases and NIDS cases in the non-influenza season

ICD-10 Code	Description	Not postcode restricted data (n ≥ 200 records)		Postcode restricted (n ≥ 200 records)
		Correlation	p	Correlation	p
T40	Poisoning by opium	0.198	0.0020	0.173	0.0070
N30	Cystitis	0.194	0.0024	0.199	0.0017
F13	Mental/behavioral disorder due to sedatives hypnotics	0.192	0.0027
A09	Infectious gastroenteritis and colitis, unspecified	0.186	0.0040
S22	Fracture of ribs	0.175	0.0063
L98	Pyogenic granuloma			0.181	0.0045
A41	Other sepsis			0.209	0.0011
A64	Unspecified sexually transmitted disease			0.164	0.0105

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