Figure 3. Sudden cardiac arrest/ventricular arrhythmia occurrence rates by prespecified strata of maximum daily ambient temperature, in degrees Celsius, among second-generation sulfonylurea users enrolled in five US state Medicaid programmes. Occurrence rates (ie, outcomes among exposed person-days) for sulfonylureas are represented by circles. We scaled the size of each data point to reflect its weight using the inverse of the variance estimate. Black-to-grey tones distinguish the sulfonylureas. Black circles=glyburide. Dark grey circles=glipizide. Light grey circles=glimepiride. Corresponding confidence bands are dark grey, medium grey and light grey, respectively. P values for quadratic terms for maximum daily ambient temperature were 0.013, 0.968 and 0.973 for glyburide, glipizide and glimepiride, respectively. P values for linear terms for maximum daily ambient temperature were 0.129, 0.249 and 0.207 for glyburide, glipizide and glimepiride, respectively; Wald test for interaction among these sulfonylureas: p=0.141. P-y, person-years.