Table 4.
Predicted prevalence ratio (PRR) of identifying diabetes using only medication lists excluding biguanides (the ratio of the sensitivities) among outpatient visits by patients with diabetes identified by the checkbox, from the combined datasets of the National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS), 2006–2010
| Univariate
|
Multivariate model A
|
Multivariate model B
|
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|---|---|---|---|---|---|---|
| PRR (95% C.I.) | P-value | PRR (95% C.I.) | P-value | PRR (95% C.I.) | P-value | |
| Age, years | 0.18 | 0.65 | 0.05 | |||
| 18–44 | Reference | Reference | Reference | |||
| 45–64 | 1.04 (0.93, 1.16) | 1.05 (0.94, 1.17) | 0.91 (0.84, 1.00) † | |||
| 65–74 | 1.12 (1.00, 1.26) † | 1.08 (0.95, 1.23) | 0.90 (0.81, 1.01) | |||
| ≥75 | 1.09 (0.95, 1.25) | 1.04 (0.89, 1.21) | 0.84 (0.74, 0.95) † | |||
|
| ||||||
| Sex | <0.01 | <0.01 | <0.01 | |||
| Female | Reference | Reference | Reference | |||
| Male | 1.10 (1.03, 1.18) † | 1.11 (1.05, 1.19) † | 1.11 (1.04, 1.17) † | |||
|
| ||||||
| Race/ethnicity | 0.16 | 0.12 | <0.01 | |||
| Non-Hispanic White | Reference | Reference | Reference | |||
| Non-Hispanic Black | 1.13 (1.01, 1.25) † | 1.15 (1.02, 1.28) † | 1.15 (1.06, 1.25) † | |||
| Hispanic | 1.06 (0.96, 1.16) | 1.07 (0.98, 1.18) | 1.13 (1.03, 1.24) † | |||
| Others | 1.08 (0.92, 1.27) | 1.08 (0.90, 1.28) | 1.12 (0.96, 1.31) | |||
|
| ||||||
| Expected sources of payment | 0.22 | 0.39 | 0.99 | |||
| Private | Reference | Reference | Reference | |||
| Medicaid | 1.11 (0.99, 1.25) | 1.11 (0.98, 1.25) | 1.01 (0.91, 1.12) | |||
| Medicare | 1.12 (1.01, 1.24) † | 1.12 (0.99, 1.27) | 1.03 (0.93, 1.13) | |||
| Self-pay | 0.97 (0.80, 1.18) | 0.98 (0.80, 1.20) | 1.01 (0.86, 1.19) | |||
| Others | 1.03 (0.86, 1.24) | 1.02 (0.83, 1.25) | 0.98 (0.83, 1.16) | |||
|
| ||||||
| Region | 0.51 | 0.43 | 0.93 | |||
| Northeast | Reference | Reference | Reference | |||
| Midwest | 1.08 (0.94, 1.23) | 1.08 (0.95, 1.24) | 1.02 (0.89, 1.18) | |||
| South | 1.00 (0.88, 1.14) | 0.99 (0.87, 1.14) | 1.03 (0.90, 1.18) | |||
| West | 1.06 (0.93, 1.21) | 1.05 (0.92, 1.20) | 1.04 (0.91, 1.20) | |||
|
| ||||||
| Number of clinic visits in the past 12 months | 0.01 | 0.17 | ||||
| 0 (new patient) | Reference | Reference | ||||
| 1–2 | 0.87 (0.72, 1.05) | 0.87 (0.74, 1.03) | ||||
| 3–5 | 1.00 (0.84, 1.19) ‡ | 0.95 (0.82, 1.11) ‡ | ||||
| ≥6 | 0.99 (0.82, 1.19) ‡ | 0.92 (0.78, 1.07) | ||||
|
| ||||||
| Number of medications | <0.01 | <0.01 | ||||
| 0–2 | Reference | Reference | ||||
| 3–5 | 3.62 (3.08, 4.24) † | 3.57 (3.06, 4.17) † | ||||
| 7–8 | 4.98 (4.30, 5.78) †‡ | 5.06 (4.37, 5.86) †‡ | ||||
|
| ||||||
| Blood test for glucose ordered | <0.01 | 0.02 | ||||
| No | Reference | Reference | ||||
| Yes | 1.14 (1.04, 1.24) † | 1.09 (1.01, 1.18) † | ||||
|
| ||||||
| Hemoglobin A1c ordered | <0.01 | <0.01 | ||||
| No | Reference | Reference | ||||
| Yes | 1.19 (1.10, 1.28) † | 1.14 (1.04, 1.24) † | ||||
|
| ||||||
| Lipids/cholesterol ordered | 0.09 | 0.01 | ||||
| No | Reference | Reference | ||||
| Yes | 1.08 (0.99, 1.17) | 0.88 (0.80, 0.96) † | ||||
|
| ||||||
| Disposition | <0.01 | 0.07 | ||||
| Return at specific time | Reference | Reference | ||||
| Refer to other physician | 1.03 (0.94, 1.14) | 1.01 (0.93, 1.10) | ||||
| Refer to ER/Admit to hospital | 1.03 (0.62, 1.72) | 1.22 (0.93, 1.60) | ||||
| Other | 0.72 (0.62, 0.84) †‡ | 0.88 (0.79, 0.98) †‡ | ||||
|
| ||||||
| Survey | 0.79 | 0.98 | 0.24 | |||
| NAMCS | Reference | Reference | Reference | |||
| NHAMCS-OPD | 1.01 (0.93, 1.11) | 1.00 (0.91, 1.09) | 0.95 (0.87, 1.04) | |||
|
| ||||||
| Survey year | 0.19 | 0.15 | 0.03 | |||
| 2006 | Reference | Reference | Reference | |||
| 2007 | 0.86 (0.76, 0.98) † | 0.86 (0.75, 0.98) † | 0.90 (0.81, 1.01) | |||
| 2008 | 0.91 (0.80, 1.03) | 0.91 (0.80, 1.04) | 0.93 (0.84, 1.02) | |||
| 2009 | 0.94 (0.82, 1.08) | 0.93 (0.81, 1.07) | 0.91 (0.81, 1.01) | |||
| 2010 | 0.89 (0.78, 1.02) | 0.88 (0.77, 1.00) | 0.84 (0.76, 0.93) † | |||
Unknown/missing category for expected payment sources and for disposition were included in the models, although their predicted prevalence ratios are not shown in the table. Multivariate models A and B did not include the number of diagnosis codes as an independent variable. The areas under the receiver-operating characteristic (ROC) curve were 0.539 and 0.580 for multivariate models A and B, respectively. P-values were estimated by Wald F-statistics for the overall significance of each variable. P-values for the pairwise comparisons for characteristics with more than two categories were estimated by t-statistics and are expressed with the following notations:
P<0.05 compared to the first category;
P<0.05 compared to the second category;
P<0.05 compared to the third category.
S.E.: standard error; ER: emergency room; PRR: predicted prevalence ratio.