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 http://www.jocmr.org

Original Article

Volume 12, Number 3, March 2020, pages 200-208


A Study of Seasonal Variation in the Effect of Add-On Sitagliptin on Blood Glucose Control in Insulin-Treated Patients With Type 2 Diabetes

Figures

Figure 1.
Figure 1. Participant flow.
Figure 2.
Figure 2. Change in HbA1c by period in which sitagliptin was started. Data are presented as mean ± standard deviation. ‡P < 0.05 versus 0 months paired t-test. HbA1c: hemoglobin A1c.
Figure 3.
Figure 3. The amount of change in HbA1c by the period in which sitagliptin was started. Data are presented as mean ± standard deviation. §P < 0.05 Tukey-Kramer test. HbA1c: hemoglobin A1c.
Figure 4.
Figure 4. The amount of change in HbA1c at 6 months from baseline (analysis of covariance). Data are presented as least squares mean ± standard error. ¶P < 0.05 ANCOVA. Groups 1 versus 2: P = 0.009, groups 1 versus 3: P = 0.001, groups 1 versus 4: P = 0.002, groups 2 versus 3: P = 0.677, groups 2 versus 4: P = 0.965, groups 3 versus 4: P = 0.662. Covariates: HbA1c and BMI at baseline, sex, age, the amount of change in BMI at 6 months from baseline, the number of insulin administrations per day, the amount of insulin per day, the use of long-acting insulin, the change in the amount of insulin administered per day at 6 months from baseline, and the concomitant use of sulfonylureas. HbA1c: hemoglobin A1c; ANCOVA: analysis of covariance; BMI: body mass index.

Tables

Table 1. Patient Characteristics
 
ItemGroup 1Group 2Group 3Group 4P
Data are presented as number (%) or mean ± SD. BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressure; eGFR: estimated glomerular filtration rate; LDL-C: low-density lipoprotein cholesterol; HDL-C: high-density lipoprotein cholesterol; TG: triglyceride; GOT: glutamate oxaloacetate transaminase; GPT: glutamate pyruvate transaminase; γ-GTP: γ-glutamyl transpeptidase; BUN: blood urea nitrogen; HbA1c: hemoglobin A1c; SD: standard deviation. *P < 0.05 ANOVA; **P < 0.05 Chi-squared test.
N172113151194
Age, years67.1 ± 10.464.4 ± 10.063.4 ± 12.163.0 ± 12.80.003*
Men/women92 (53.5%)/80 (46.5%)51 (45.1%)/62 (54.9%)73 (48.3%)/78 (51.7%)79 (40.7%)/115 (59.3%)0.101
Disease duration, years17.7 ± 9.117.2 ± 10.116.9 ± 8.516.6 ± 8.90.731
Retinopathy58 (66.3%)37 (67.3%)60 (60.3%)63 (67.5%)0.498
Cataract34 (80.2%)22 (80.5%)24 (84.1%)41 (78.9%)0.666
Neuropathy63 (63.4%)35 (69%)52 (65.6%)66 (66%)0.807
Nephropathy69 (59.9%)49 (56.6%)59 (60.9%)76 (60.8%)0.888
Cerebrovascular disorder18 (89.5%)9 (92%)14 (90.7%)15 (92.3%)0.803
Myocardial infarction and angina29 (83.1%)18 (84.1%)23 (84.8%)44 (77.3%)0.249
Arteriosclerosis obliterans19 (89%)8 (92.9%)11 (92.7%)22 (88.7%)0.412
Hypertension90 (47.7%)71 (37.2%)86 (43%)116 (40.2%)0.304
Dyslipidemia97 (43.6%)73 (35.4%)105 (30.5%)126 (35.1%)0.095
Fatty liver46 (73.3%)45 (60.2%)44 (70.9%)71 (63.4%)0.055
Medication information
  Dosage of sitagliptin
    25 mg/day36 (20.9%)29 (25.7%)24 (15.9%)27 (13.9%)0.226
    50 mg/day135 (78.5%)83 (73.5%)126 (83.4%)166 (85.6%)
    100 mg/day1 (0.6%)1 (0.9%)1 (0.7%)1 (0.5%)
  Classification of insulin
    Three times or more (no long-acting type)39 (22.7%)23 (20.4%)27 (17.9%)49 (25.3%)0.410
    Three times or more (including a long-acting type)60 (34.9%)51 (45.1%)57 (37.7%)59 (30.4%)
    Twice, mixed type30 (17.4%)14 (12.4%)28 (18.5%)37 (19.1%)
    Administered once, long-acting type28 (16.3%)21 (18.6%)30 (19.9%)37 (19.1%)
    Others15 (8.7%)4 (3.5%)9 (6%)12 (6.2%)
  Number of insulin administrations2.7 ± 1.12.9 ± 1.12.7 ± 1.12.6 ± 1.00.197
  Total amount of insulin administered, U/day30.2 ± 23.033.3 ± 22.233.8 ± 21.532.1 ± 21.70.473
  Previous treatment with insulin, years6.9 ± 6.17.3 ± 6.96.7 ± 4.86.0 ± 4.90.341
  Concomitant medications
    Sulfonylurea25 (85.5%)16 (85.8%)38 (74.8%)41 (78.9%)0.041**
    Biguanide59 (65.7%)40 (64.6%)67 (55.6%)81 (58.2%)0.200
    α-Glucosidase inhibitors38 (77.9%)17 (85%)25 (83.4%)49 (74.7%)0.091
    Thiazolidine12 (93%)6 (94.7%)15 (90.1%)10 (94.8%)0.313
Laboratory data at the start of sitagliptin
  HbA1c, %8.53 ± 1.248.56 ± 1.258.70 ± 1.318.73 ± 1.320.404
  Fasting blood glucose, mg/dL202.3 ± 67.2169.4 ± 50.6178.1 ± 77.7194.4 ± 73.50.098
  Casual blood glucose, mg/dL195.9 ± 86.8195.1 ± 94.8194.7 ± 71.8207.4 ± 84.70.516
  BMI, kg/m224.19 ± 3.8225.40 ± 4.9426.05 ± 4.3125.75 ± 4.66< 0.001*
  SBP, mm Hg131.6 ± 13.2128.4 ± 14.2130.7 ± 15.8131.1 ± 17.20.396
  DBP, mm Hg74.2 ± 9.372.0 ± 10.275.4 ± 12.076.2 ± 10.90.011*
  eGFR, mL/min/1.73 m277.1 ± 21.876.1 ± 23.675.5 ± 21.875.9 ± 24.30.957
  LDL-C, mg/dL110.7 ± 25.1109.6 ± 29.6108.1 ± 30.3106.3 ± 29.60.623
  HDL-C, mg/dL60.6 ± 15.054.2 ± 18.253.5 ± 14.954.3 ± 14.6< 0.001*
  TG, mg/dL151.1 ± 127.2163.9 ± 132.8173.5 ± 96.2176.7 ± 117.70.246
  GOT, U/L25.2 ± 15.724.2 ± 18.025.0 ± 12.124.5 ± 15.60.960
  GPT, U/L26.3 ± 20.927.5 ± 21.130.6 ± 22.027.1 ± 19.00.383
  γ-GTP, U/L46.8 ± 80.545.4 ± 44.645.4 ± 40.043.7 ± 54.80.978
  BUN, mg/dL18.3 ± 5.515.4 ± 4.416.3 ± 5.115.5 ± 4.90.002*
  Uric acid, mg/dL4.9 ± 1.35.1 ± 1.35.2 ± 1.55.0 ± 1.40.711

 

Table 2. Number of Patients Who Developed Hypoglycemia
 
n0 - 3 months4 - 6 months7 - 9 months10 - 12 monthsBy 12 months from baseline
Data are n (%). N.S. Chi-squared test. N.S.: no significance.
Group 117217 (9.9%)8 (4.7%)9 (5.2%)8 (4.7%)25 (14.5%)
Group 211310 (8.8%)5 (4.4%)6 (5.3%)4 (3.5%)16 (14.2%)
Group 31514 (2.6%)0 (0%)3 (2.0%)6 (4.0%)12 (7.9%)
Group 419413 (6.7%)10 (5.2%)8 (4.1%)11 (5.7%)23 (11.9%)
P0.0940.0540.4440.8180.275