Table 1—

Case-control and cohort studies

StudyPopulation (age)*Definition of type 2 diabetesRisk of type 2 diabetes (95% CI)Follow-up (years)/(rate)Major limitations
Case-control study
 Gurwitz et al. (11)4,794 case and 3,211 control subjects (New Jersey Medicaid administrative database) (≥35 years)New users of type 2 diabetes medicationThiazides: 1.0 (referent); AB: 1.1 (0.75–2.0); ACE inhibitors: 1.2 (0.9–1.5); BB: 0.95 (0.8–1.1); CCB: 1.1 (0.9–1.3)Not applicable1) Missed untreated cases of type 2 diabetes; 2) no control for BMI, baseline glucose, FH, or exercise
Cohort studies
 Bengtsson et al. (12)1,462 women from Sweden (38–60 years)Two FPG levels ≥7.0 mmol/l or physician-reported diagnosisRR compared with women not taking antihypertensive drugs: diuretics: 3.4 (1.5–7.9); BB: 5.7 (2.6–12.5); diuretics and BB: 11.4 (5.0–26.0)12 (79%)1) No adjustment for hypertension status, concomitant meds, exercise, FH, or SES
 Gress et al. (13)3,804 hypertensive subjects from the Atherosclerosis Risk in Communities (ARIC) cohort in the U.S. (45–64 years). Hypertensive subgroup of original cohort of 13,877 patientsFPG ≥7.0 mmol/l or RPG ≥11.1 mmol/l or use of antidiabetic agent or physician-reported diagnosisHR of diabetes compared to no therapy: thiazides: 0.91 (0.73–1.13); BB: 1.28 (1.04–1.57); CCB: 1.17 (0.83–1.66); ACE inhibitors: 0.98 (0.72–1.34)6 (not specified; follow-up rate in larger cohort was 90%)1) No major limitations
 Gurwitz et al. (14)2,737 subjects from the East Boston Senior Health Project (≥65 years) (cohort divided into two 3-year follow-up intervals)New use of an antidiabetic agent at the end of two 3-year intervalsRR compared to no antihypertensive therapy: thiazides: 0.99 (0.59–1.6); nonthiazides: 1.8 (1.1–3.0)Two 3-year periods (91%)1) Missed cases of untreated diabetes; 2) no adjustment for baseline glucose, race, FH, SES, or concomitant meds 3) nonthiazides analyzed as one group
 Morales et al. (15) (San Antonio Heart Study)146 hypertensive Mexican-American and Caucasian subjects (25–64 years)FPG ≥7.8 mmol/l or RPG ≥11.1 mmol/l or use of antidiabetic agentUsers of thiazides and/or BB compared with users of other agents and untreated hypertensives: OR 1.2 (0.26–5.46)8 (80%)1) No adjustment for concomitant meds, exercise, FH, or SES; 2) diuretics and BB analyzed as one group and compared to other treated and untreated hypertensives; 3) small sample size
 Mykkanen et al. (16)480 hypertensive patients from Finland (65–74 years)FPG ≥7.8 mmol/l or PG ≥11.1 mmol/l 2-h post-OGTT or physician reportedDiuretics plus BB versus untreated hypertensive patients: OR 2.1 (1.1–4.3)3.5 (88%)1) No adjustment for concomitant meds, exercise, FH, or SES; 2) diuretics and BB combined into one category; 3) small sample size
 Rajala et al. (17)207 subjects with IGT from FinlandOne 2-h level ≥11.1 mmol/l on OGTT or 2 FPG levels ≥6.7 mmol/lCompared with nonhypertensives: thiazides ± other antihypertensive agents: OR 7.7 (2.1–28.2); other agents (BB, CCB, ACE inhibitors, AB): OR 2.6 (1.0–6.7)4.6 (84%)1) Separate analysis not performed for each antihypertensive class because of very small sample size; 2) no adjustment for age, sex, exercise, concomitant meds, SES, or FH; 3) control group was nonhypertensive patients
 Samuelsson et al. (18)659 hypertensive men from Sweden (47–54 years)Annual urine dipstick for glucosuria, confirmed by a FPG ≥7.0 mmol/lUsers of BB compared with nonusers: RR 2.1 (1.2–3.9); users of thiazides compared with nonusers: RR 0.74 (0.5–1.2)10 (not specified)1) Number of patients on multi-drug therapy and combined BB/thiazide therapy (excluded) unclear; 2) no adjustment for age, baseline glucose, concomitant meds, SES, exercise, or FH
 Skarfors et al. (19)1,834 Swedish men (47–53 years)FPG ≥7.8 mmol/l or PG ≥11.1 mmol/l 2-h post-OGTTUsers of thiazides, BB or hydralazine compared with nonusers: OR 1.7 (1.1–2.6)10.2 (not specified)1) Separate analysis not performed for each antihypertensive class; 2) no adjustment for age, exercise, SES, or concomitant meds
  • *

    * Patients with diabetes at baseline are not included in the sample sizes reported.

  • Refers to the percentage of patients with complete follow-up rounded up. AB, α-blockers; BB, β-blockers; BP, blood pressure; CCB, calcium channel blockers; FPG, fasting plasma glucose; FH, family history; OGTT, oral glucose tolerance test; RPG, random plasma glucose; SES, socioeconomic status.