Table 2.
Predictors of Metabolic Control, Using Multiple Adjusted Estimated Median Hemoglobin A1c (HbA1c), Ratio of Log-HbA1c, and Proportion of Patients with HbA1c >7.5% or >9% by Patient Characteristics and Aspects of Diabetes Management
| Variable | Median HbA1c (IQR) | HbA1c mean ratioa | P | HbA1c >7.5% | Odds ratio HbA1c >7.5% (CI)a | P | HbA1c >9% | Odds ratio HbA1c >9% (CI)a | P |
|---|---|---|---|---|---|---|---|---|---|
| Gender | |||||||||
| Male |
7.80 (7.20–8.60) |
1.00 |
0.01 |
62.47 |
1.00 |
0.019 |
16.84 |
1.00 |
0.204 |
| Female |
7.96 (7.30–8.80) |
1.02 (1.00–1.04) |
|
67.12 |
1.45 (1.06–1.98) |
|
20.13 |
1.28 (0.87–1.90) |
|
| Age at measurement (years)b | |||||||||
| 1 |
7.60 (6.90–8.30) |
1.00 |
<0.001 |
52.94 |
1.00 |
<0.001 |
5.88 |
1.00 |
<0.001 |
| 5 |
7.70 (7.20–8.20) |
0.97 (0.95–0.98) |
|
62.13 |
0.72 (0.53–0.96) |
|
4.14 |
0.86 (0.52–1.42) |
|
| 10 |
7.70 (7.10–8.30) |
0.94 (0.91–0.97) |
|
57.11 |
0.51 (0.27–0.94) |
|
10.02 |
0.84 (0.29–2.39) |
|
| 15 |
8.10 (7.40–9.00) |
0.96 (0.93–1.00) |
|
71.20 |
0.64 (0.32–1.25) |
|
24.63 |
2.72 (0.91–8.08) |
|
| 20 |
7.90 (7.20–8.85) |
0.95 (0.91–0.99) |
|
66.30 |
0.35 (0.16–0.77) |
|
21.68 |
2.76 (0.83–9.20) |
|
| Duration of diabetes (years)b | |||||||||
| 1 |
7.40 (6.80–8.14) |
1.00 |
<0.001 |
47.75 |
1.00 |
<0.001 |
8.92 |
1.00 |
<0.001 |
| 5 |
8.00 (7.30–8.80 |
1.11 (1.10–1.13) |
|
68.26 |
7.89 (5.87–10.60) |
|
21.80 |
6.27 (4.09–9.59) |
|
| 10 |
8.05 (7.50–8.90) |
1.15 (1.12–1.18) |
|
73.60 |
15.07 (9.31–24.38) |
|
21.25 |
9.49 (4.99–18.05) |
|
| 15 |
8.05 (7.40–8.90 |
1.17 (1.13–1.21) |
|
71.14 |
22.63 (11.09–46.18) |
|
22.82 |
9.77 (3.75–25.46) |
|
| Year of measurementb | |||||||||
| 2001 |
9.10 (8.20–10.15) |
1.00 |
<0.001 |
89.05 |
1.00 |
<0.001 |
52.06 |
1.00 |
<0.001 |
| 2006 |
7.65 (7.10–8.20) |
0.89 (0.88–0.90) |
|
54.70 |
0.11 (0.08–0.14) |
|
10.57 |
0.06 (0.04–0.08) |
|
| 2011 |
7.80 (7.20–8.32) |
0.89 (0.87–0.90) |
|
62.78 |
0.11 (0.08–0.16) |
|
9.36 |
0.04 (0.03–0.06) |
|
| BMI SDSb | |||||||||
| 0 |
7.75 (7.10–8.56) |
1.00 |
0.053 |
58.92 |
1.00 |
0.001 |
15.50 |
1.00 |
0.039 |
| −3 |
8.18 (8.06–8.46) |
1.03 (1.00–1.07) |
|
53.45 |
3.22 (1.39–7.49) |
|
3.45 |
4.89 (1.49–16.04) |
|
| −1 |
7.70 (7.10–8.55) |
1.01 (1.00–1.02) |
|
57.45 |
1.26 (1.02–1.56) |
|
17.60 |
1.35 (1.01–1.82) |
|
| 1 |
7.95 (7.32–8.80) |
1.00 (0.99–1.01) |
|
67.39 |
1.35 (1.10–1.65) |
|
20.52 |
1.29 (0.99–1.67) |
|
| 3 |
7.75 (7.10–8.20) |
0.99 (0.96–1.01) |
|
63.04 |
1.97 (1.13–3.43) |
|
13.04 |
1.45 (0.72–2.93) |
|
| Treatment modality | |||||||||
| MDI |
8.40 (7.50–9.50) |
1.00 |
<0.001 |
74.58 |
1.00 |
0.004 |
33.43 |
1.00 |
<0.001 |
| CSII | 7.80 (7.20–8.40) | 0.98 (0.97–0.99) | 61.25 | 0.72 (0.57–0.91) | 13.19 | 0.61 (0.46–0.80) | |||
Estimates are derived from multiple linear and logistic mixed models including gender, age at measurement, year of measurement, diabetes duration, body mass index (BMI) SD score (SDS), and treatment modality (multiple daily injections [MDI] or continuous subcutaneous insulin infusion [CSII]) as fixed effects. Values for age, duration of diabetes, and year of measurement, which were flexibly modeled using restricted cubic splines, present estimated associations between the variables and the outcomes.
Each estimate is adjusted for all the other variables in the table; a value of 1.00 indicates the reference values.
Restricted cubic splines were used to flexibly model the relationship between the covariate and the outcome. The variables were not categorized, and the values of the covariates do not represent categories. The descriptive statistics are based on the subset of patients with the chosen value of the covariate (±0.5 for BMI SDS).
CI, confidence interval; IQR, interquartile range.