Use of electronic health records from a statewide health information exchange to support public health surveillance of diabetes and hypertension

Table 2 Sensitivity, positive predictive value, and proportion of patients classified as having diabetes and hypertension by different methods, using matched patient-level data in a mid-size health system (Database A) to those systems patients in the Health Information Exchange (Database B), Utah — 2015 (N = 72,356)

Variables	Sensitivity^a	Positive Predictive Value^a	Proportion Classified in Database A	Proportion Classified in Database B	Absolute Difference	Percent Difference
Variables	%	%	%	%	%	%
Classified as having Diabetes based on:
A1C Test Results^b	22.9	36.0	1.2	0.8	0.4	40.0
Diagnosis Codes	52.8	76.9	11.6	8.0	3.6	36.7
Both^c	55.7	77.8	11.6	8.3	3.3	33.2
Classified as having Hypertension based on:
Blood Pressure Readings^b	16.5	54.4	3.0	0.9	2.1	107.7
Diagnosis Codes	57.4	70.6	20.7	16.8	3.9	20.8
Both^c	57.1	71.4	21.5	17.2	4.3	22.2

^aUsing Database A as the standard
^bOnly captures persons with either uncontrolled diabetes or uncontrolled hypertension
^cUsed as measure of disease prevalence

ISSN: 1471-2458