Table 2 Baseline characteristics and performance of candidate algorithms among people in the derivation cohort, stratified by diabetes type. Candidate algorithms developed using encounter codes (“code algorithms”) or prescriptions (“prescription algorithms”) are also shown. For each algorithm, values in the Type 1 and 2 columns indicate the number and percentage of individuals satisfying the algorithm (sensitivity). Positive predictive values for classifying type 1 diabetes are shown in the right column. The best 4 algorithms are indicated by the letters in parentheses (A–D; see text for selection criteria)
Type 1 (n = 60) | Type 2 (n = 10,136) | Positive Predictive Value (%) | |
|---|---|---|---|
Demographic Characteristics | |||
Age at diagnosis (years; mean, standard deviation) | 22.7 (12.6) | 55.9 (11.4) | |
< 18 | 16 (26.7) | 20 (0.2) | |
18–39 | 33 (55.0) | 768 (7.6) | |
≥ 40 years | 11 (18.3) | 9348 (92.3) | |
Female | 32 (53.3) | 4456 (43.9) | |
Coding Characteristics* | |||
Number of type 1 codes (median, interquartile range) | 3.0 (4.0) | 0.0 (0.0) | |
Total number of type 1principal codes (median, interquartile range) | 2.0 (2.5) | 0.0 (0.0) | |
Total number of type 1 mixed codes (median, interquartile range) | 1.0 (2.0) | 0.0 (0.0) | |
Number of type 2 codes (median, interquartile range) | 0.0 (1.0) | 1.0 (3.0) | |
Total number of type 2 principal codes (median, interquartile range) | 0.0 (0.0) | 1.0 (2.0) | |
Total number of type 2 mixed codes (median, interquartile range) | 0.0 (0.0) | 1.0 (2.0) | |
Candidate Code Algorithms* | |||
At least 1 type 1 code | 50 (83.3) | 142 (1.4) | 26.0 |
At least 1 type 1 principal code | 42 (70.0) | 65 (0.6) | 39.2 |
At least 1 type 1 mixed code | 38 (63.3) | 108 (1.1) | 26.0 |
At least 1 type 2 code | 43 (71.7) | 92 (0.9) | 31.8 |
At least 1 type 2 principal code | 29 (48.3) | 25 (0.2) | 53.7 |
At least 1 type 2 mixed code | 21 (35.0) | 66 (0.6) | 24.1 |
Ratio of type 1 to type 2 codes ≥ 0.5 (A) | 50 (83.3) | 97 (1.0) | 34.0 |
Ratio of type 1 to type 2 codes ≥ 0.75 | 49 (81.7) | 81 (0.8) | 37.7 |
Ratio of type 1 to type 2 codes ≥ 1 | 49 (81.7) | 78 (0.8) | 38.6 |
Ratio of type 1 to type 2 codes ≥ 2 | 47 (78.3) | 47 (0.5) | 50.0 |
Ratio of type 1 to type 2 codes ≥ 3 | 46 (76.7) | 38 (0.4) | 54.8 |
Ratio of type 1 to type 2 codes ≥ 4 (B) | 43 (71.7) | 32 (0.3) | 57.3 |
Candidate Prescription Algorithms† | |||
At least 1 insulin prescription | 59 (98.3) | 3408 (33.6) | 1.7 |
within 90 days (C) | 58 (96.7) | 615 (6.1) | 8.6 |
within 180 days | 58 (96.7) | 715 (7.1) | 7.5 |
within 365 days | 58 (96.7) | 844 (8.3) | 6.4 |
At least 1 insulin prescription with no other glucose-lowering medication prescription | 36 (60.0) | 80 (0.8) | 31.0 |
within 90 days | 43 (71.7) | 362 (3.6) | 10.6 |
within 180 days | 44 (73.3) | 483 (4.8) | 8.4 |
within 365 days | 45 (75.0) | 653 (6.4) | 6.4 |
At least 1 insulin prescription with no other glucose-lowering medication prescription except metformin | 50 (83.3) | 275 (2.7) | 15.4 |
within 90 days | 53 (88.3) | 451 (4.4) | 10.5 |
within 180 days | 54 (90.0) | 566 (5.6) | 8.7 |
within 365 days | 54 (90.0) | 727 (7.2) | 6.9 |
Multiple daily injections‡ | 47 (78.3) | 273 (2.7) | 14.7 |
within 90 days | 7 (11.7) | 5 (0.0) | 58.3 |
within 180 days | 8 (13.3) | 9 (0.1) | 47.1 |
within 365 days | 12 (20.0) | 13 (0.1) | 48.0 |
Multiple daily injections with no other glucose-lowering medication prescription (D) | 32 (53.3) | 9 (0.1) | 78.0 |
within 90 days | 7 (11.7) | 2 (0.0) | 77.8 |
within 180 days | 8 (13.3) | 6 (0.1) | 571 |
within 365 days | 12 (20.0) | 11 (0.1) | 52.2 |
Multiple daily injections with no other glucose-lowering medication prescription except metformin | 42 (70.0) | 26 (0.3) | 61.8 |
within 90 days | 7 (11.7) | 2 (0.0) | 77.8 |
within 180 days | 8 (13.3) | 6 (0.1) | 57.1 |
within 365 days | 12 (20.0) | 11 (0.1) | 52.2 |
At least 1 metformin prescription | 22 (36.7) | 8979 (88.6) | 0.2 |
Other glucose-lowering medication prescription excluding insulin and metformin | 10 (16.7) | 7673 (75.7) | 0.2 |