J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://jocmr.elmerjournals.com

Original Article

Volume 17, Number 3, March 2025, pages 164-173

Predictive Factors for Diagnosing Diabetic Ketoacidosis or Simple Hyperglycemia in Adults With High Blood Glucose: The “1-DKA Alert” Study

Figure 3. Calibration plot for predicted and observed probabilities of diabetic ketoacidosis. CI: confidence interval.

**Table 1.** Baseline Characteristics of Patients With Diabetic Ketoacidosis and Simple Hyperglycemia
Baseline characteristics	Missing	Diabetic ketoacidosis (n = 56), mean ± SD	Simple hyperglycemia (n = 218), mean ± SD	P value
SD: standard deviation; bpm: beats per minute; SpO₂: peripheral capillary oxygen saturation; Cr: Creatinine; eGFR: estimated glomerular filtration rate; CKD: chronic kidney disease.
Female, n (%)	0	31 (55.4)	114 (52.3)	0.765
Age (years)	0	52.9 ± 18.5	60.4 ± 13.7	0.001
Body mass index (kg/m²)	4	22.4 ± 4.6	23.4 ± 5.0	0.209
Symptoms, n (%)	0	54 (96.4)	124 (56.9)	< 0.001
Dyspnea	0	42 (75.0)	74 (33.9)	< 0.001
Gastrointestinal/hepatobiliary	0	23 (41.1)	55 (25.2)	0.030
Fever	0	18 (32.1)	55 (25.2)	0.312
Vital signs
Temperature (°C)	0	36.7 ± 1.0	36.8 ± 1.1	0.613
Respiratory rate	0	27.4 ± 8.7	22.1 ± 5.6	< 0.001
Systolic blood pressure (mm Hg)	0	124.8 ± 34.3	138.3 ± 31.9	0.006
Diastolic blood pressure (mm Hg)	0	74.7 ± 20.5	78.4 ± 18.6	0.199
Mean arterial pressure (mm Hg)	0	91.4 ± 24.1	98.3 ± 21.3	0.035
Pulse rate (bpm)	0	112.4 ± 22.3	95.6 ± 21.8	< 0.001
SpO₂ (%)	0	96.5 ± 6.0	97.1 ± 3.5	0.348
Initial capillary blood glucose (mg/dL)	0	495.3 ± 117.0	420.7 ± 108.5	< 0.001
Initial blood glucose (mg/dL)	0	594.8 ± 299.5	431.3 ± 147.7	< 0.001
Hemoglobin A1c (prior visit) (%)	95	10.1 ± 3.4	9.3 ± 3.0	0.173
Hemoglobin A1c (latest visit) (%)	115	12.2 ± 3.1	10.5 ± 2.9	0.001
Cr (prior visit) (mg/dL) median (IQR)	46	0.87 (0.70, 1.28)	0.94 (0.7, 1.43)	0.330
eGFR (prior visit) (mL/min/1.73 m²), median (IQR)	46	87.26 (54.86, 107.21)	78.76 (46.75, 101.26)	0.135
Cr (latest visit) (mg/dL), median (IQR)	0	1.35 (0.67, 2.76)	1.11 (0.75, 1.70)	0.263
eGFR (latest visit) (mL/min/1.73 m²), median (IQR)	0	56.24 (21.60, 104.55)	63.64 (41.13, 94.71)	0.604
Urine ketone, median (IQR)	0	3 (2, 4)	0 (0, 0)	< 0.001
Suspected infection, n (%)	0	46 (82.1)	104 (47.7)	< 0.001
Presumed source of infection, n (%)
No infection	0	11 (19.6)	113 (51.8)	< 0.001
Pneumonia	0	15 (26.8)	24 (11.0)
Urinary tract infection	0	13 (23.2)	31 (14.2)
Septicemia	0	9 (16.1)	16 (7.3)
Gastrointestinal/hepatobiliary infection	0	1 (1.8)	5 (2.4)
Infected wound	0	0 (0)	16 (7.3)
Other	0	7 (12.5)	13 (6.0)
First diagnosis: hyperglycemia, n (%)	0	2 (3.6)	22 (10.1)	0.183
Previous diabetic ketoacidosis, n (%)	0	14 (25.0)	9 (4.1)	< 0.001
Diabetes mellitus, n (%)	0	54 (96.4)	196 (89.9)	0.183
Type of diabetes mellitus (DM), n (%)
Undiagnosed DM	0	2 (3.6)	22 (10.1)	< 0.001
Type 1 DM	0	8 (14.3)	3 (1.4)
Type 2 DM	0	46 (82.1)	193 (88.5)
CKD stages 3 - 5, n (%)	0	18 (32.1)	81 (37.2)	0.535
Hypertension, n (%)	0	33 (58.9)	154 (70.6)	0.108
Dyslipidemia, n (%)	0	24 (42.9)	120 (55.1)	0.133
Insulin usage, n (%)	0	39 (69.6)	64 (29.4)	< 0.001
Type of insulin, n (%)
Multiple dose regular insulin	169	6 (15.4)	12 (18.2)	0.794
Isophane insulin	170	9 (23.1)	14 (21.5)	1
Mixtard insulin	170	31 (79.5)	41 (63.1)	0.124
Oral hypoglycemic agent used, n (%)	0	25 (44.6)	138 (63.3)	0.014
Type of oral hypoglycemic agents, n (%)
Sulfonylureas (glipizide)	110	9 (36.0)	69 (49.6)	0.277
Biguanides (metformin)	110	24 (96.0)	112 (80.6)	0.081
Thiazolidinediones (pioglitazone)	110	13 (52.0)	45 (32.4)	0.071
Diet control alone, n (%)	0	2 (3.6)	21 (9.6)	0.183
Poor compliance, n (%)	0	42 (75.0)	97 (44.5)	< 0.001

Table 1. Baseline Characteristics of Patients With Diabetic Ketoacidosis and Simple Hyperglycemia

Baseline characteristics

Missing

Diabetic ketoacidosis (n = 56), mean ± SD

Simple hyperglycemia (n = 218), mean ± SD

P value

SD: standard deviation; bpm: beats per minute; SpO₂: peripheral capillary oxygen saturation; Cr: Creatinine; eGFR: estimated glomerular filtration rate; CKD: chronic kidney disease.

Female, n (%)

31 (55.4)

114 (52.3)

0.765

Age (years)

52.9 ± 18.5

60.4 ± 13.7

0.001

Body mass index (kg/m²)

22.4 ± 4.6

23.4 ± 5.0

0.209

Symptoms, n (%)

54 (96.4)

124 (56.9)

< 0.001

Dyspnea

42 (75.0)

74 (33.9)

< 0.001

Gastrointestinal/hepatobiliary

23 (41.1)

55 (25.2)

0.030

Fever

18 (32.1)

55 (25.2)

0.312

Vital signs

Temperature (°C)

36.7 ± 1.0

36.8 ± 1.1

0.613

Respiratory rate

27.4 ± 8.7

22.1 ± 5.6

< 0.001

Systolic blood pressure (mm Hg)

124.8 ± 34.3

138.3 ± 31.9

0.006

Diastolic blood pressure (mm Hg)

74.7 ± 20.5

78.4 ± 18.6

0.199

Mean arterial pressure (mm Hg)

91.4 ± 24.1

98.3 ± 21.3

0.035

Pulse rate (bpm)

112.4 ± 22.3

95.6 ± 21.8

< 0.001

SpO₂ (%)

96.5 ± 6.0

97.1 ± 3.5

0.348

Initial capillary blood glucose (mg/dL)

495.3 ± 117.0

420.7 ± 108.5

< 0.001

Initial blood glucose (mg/dL)

594.8 ± 299.5

431.3 ± 147.7

< 0.001

Hemoglobin A1c (prior visit) (%)

10.1 ± 3.4

9.3 ± 3.0

0.173

Hemoglobin A1c (latest visit) (%)

115

12.2 ± 3.1

10.5 ± 2.9

0.001

Cr (prior visit) (mg/dL) median (IQR)

0.87 (0.70, 1.28)

0.94 (0.7, 1.43)

0.330

eGFR (prior visit) (mL/min/1.73 m²), median (IQR)

87.26 (54.86, 107.21)

78.76 (46.75, 101.26)

0.135

Cr (latest visit) (mg/dL), median (IQR)

1.35 (0.67, 2.76)

1.11 (0.75, 1.70)

0.263

eGFR (latest visit) (mL/min/1.73 m²), median (IQR)

56.24 (21.60, 104.55)

63.64 (41.13, 94.71)

0.604

Urine ketone, median (IQR)

3 (2, 4)

0 (0, 0)

< 0.001

Suspected infection, n (%)

46 (82.1)

104 (47.7)

< 0.001

Presumed source of infection, n (%)

No infection

11 (19.6)

113 (51.8)

< 0.001

Pneumonia

15 (26.8)

24 (11.0)

Urinary tract infection

13 (23.2)

31 (14.2)

Septicemia

9 (16.1)

16 (7.3)

Gastrointestinal/hepatobiliary infection

1 (1.8)

5 (2.4)

Infected wound

0 (0)

16 (7.3)

Other

7 (12.5)

13 (6.0)

First diagnosis: hyperglycemia, n (%)

2 (3.6)

22 (10.1)

0.183

Previous diabetic ketoacidosis, n (%)

14 (25.0)

9 (4.1)

< 0.001

Diabetes mellitus, n (%)

54 (96.4)

196 (89.9)

0.183

Type of diabetes mellitus (DM), n (%)

Undiagnosed DM

2 (3.6)

22 (10.1)

< 0.001

Type 1 DM

8 (14.3)

3 (1.4)

Type 2 DM

46 (82.1)

193 (88.5)

CKD stages 3 - 5, n (%)

18 (32.1)

81 (37.2)

0.535

Hypertension, n (%)

33 (58.9)

154 (70.6)

0.108

Dyslipidemia, n (%)

24 (42.9)

120 (55.1)

0.133

Insulin usage, n (%)

39 (69.6)

64 (29.4)

< 0.001

Type of insulin, n (%)

Multiple dose regular insulin

169

6 (15.4)

12 (18.2)

0.794

Isophane insulin

170

9 (23.1)

14 (21.5)

Mixtard insulin

170

31 (79.5)

41 (63.1)

0.124

Oral hypoglycemic agent used, n (%)

25 (44.6)

138 (63.3)

0.014

Type of oral hypoglycemic agents, n (%)

Sulfonylureas (glipizide)

110

9 (36.0)

69 (49.6)

0.277

Biguanides (metformin)

110

24 (96.0)

112 (80.6)

0.081

Thiazolidinediones (pioglitazone)

110

13 (52.0)

45 (32.4)

0.071

Diet control alone, n (%)

2 (3.6)

21 (9.6)

0.183

Poor compliance, n (%)

42 (75.0)

97 (44.5)

< 0.001

**Table 2.** Final multivariable risk ratio regression analysis for the predictive model
Predictors	Diabetic ketoacidosis
mRR: multivariable risk ratio; DM: diabetes mellitus; CI: confidence interval.
Initial capillary blood glucose (mg/dL)	1	1.00, 1.00	0.043
History of DM	Reference
Type 1 DM	2.93	1.00, 8.52	0.049
Type 2 DM	2.14	0.83, 5.53	0.117
Insulin usage	2.79	1.63, 4.77	< 0.001
Poor compliance	2.43	1.45, 4.05	0.001
Respiratory rate	1.04	1.01, 1.06	0.001
Suspected infection	2.51	1.32, 4.78	0.005

Table 2. Final multivariable risk ratio regression analysis for the predictive model

Predictors

Diabetic ketoacidosis

mRR

95% CI

P value

mRR: multivariable risk ratio; DM: diabetes mellitus; CI: confidence interval.

Initial capillary blood glucose (mg/dL)

1.00, 1.00

0.043

History of DM

Reference

Type 1 DM

2.93

1.00, 8.52

0.049

Type 2 DM

2.14

0.83, 5.53

0.117

Insulin usage

2.79

1.63, 4.77

< 0.001

Poor compliance

2.43

1.45, 4.05

0.001

Respiratory rate

1.04

1.01, 1.06

0.001

Suspected infection

2.51

1.32, 4.78

0.005

**Table 3.** Internal Validation Using the Bootstrap Resampling Method
Parameters	Apparent performance	Bootstrap performance
AuROC: area under the receiver operating characteristic curve; CITL: calibration-in-the-large; E:O ratio: expected-to-observed outcomes ratio.
AuROC	0.8777 (0.8294, 0.9259)	0.8770 (0.8330, 0.9310)
Slope	1.000 (0.730, 1.270)	0.991 (0.743, 1.285)
E:O ratio	1.000	1.004
CITL	0.000 (-0.367, 0.367)	0.002 (-0.386, 0.425)
Bootstrap shrinkage	-	0.991

Table 3. Internal Validation Using the Bootstrap Resampling Method

Parameters

Apparent performance

Bootstrap performance

AuROC: area under the receiver operating characteristic curve; CITL: calibration-in-the-large; E:O ratio: expected-to-observed outcomes ratio.

AuROC

0.8777 (0.8294, 0.9259)

0.8770 (0.8330, 0.9310)

Slope

1.000 (0.730, 1.270)

0.991 (0.743, 1.285)

E:O ratio

1.000

1.004

CITL

0.000 (-0.367, 0.367)

0.002 (-0.386, 0.425)

Bootstrap shrinkage

0.991

**Table 4.** Accuracy and Diagnostic Indices at Different Probability Cut-Points for Predicting DKA
Cut-point	DKA (n = 56)	Simple hyperglycemia (n = 218)	Total	Sensitivity	Specificity	PPV	NPV
DKA: diabetic ketoacidosis; PPV: positive predictive value; NPV: negative predictive value.
Probability > 15%	50 (18.2%)	67 (24.5%)	117	89.3%	78.1%	42.7%	96.2%
Probability ≤ 15%	6 (2.2%)	151 (55.1%)	157
Probability > 19.4%	43 (15.7%)	42 (15.3%)	85	76.8%	80.7%	50.6%	93.1%
Probability ≤ 19.4%	13 (4.7%)	176 (64.3%)	189
Probability > 25%	38 (13.9%)	25 (9.1%)	63	67.9%	88.5%	60.3%	91.5%
Probability ≤ 25%	18 (6.6%)	193 (70.4%)	211

Table 4. Accuracy and Diagnostic Indices at Different Probability Cut-Points for Predicting DKA

Cut-point

DKA (n = 56)

Simple hyperglycemia (n = 218)

Total

Sensitivity

Specificity

PPV

NPV

DKA: diabetic ketoacidosis; PPV: positive predictive value; NPV: negative predictive value.

Probability > 15%

50 (18.2%)

67 (24.5%)

117

89.3%

78.1%

42.7%

96.2%

Probability ≤ 15%

6 (2.2%)

151 (55.1%)

157

Probability > 19.4%

43 (15.7%)

42 (15.3%)

76.8%

80.7%

50.6%

93.1%

Probability ≤ 19.4%

13 (4.7%)

176 (64.3%)

189

Probability > 25%

38 (13.9%)

25 (9.1%)

67.9%

88.5%

60.3%

91.5%

Probability ≤ 25%

18 (6.6%)

193 (70.4%)

211