Table 1.
Characteristics of study populations
| Reference | Nr of subjects | Follow-up | Diagnosis | Age (y) | Antihypertensive drugs | New | Observation time | Other selection |
|---|---|---|---|---|---|---|---|---|
| Jones et al (1995), UK Mediplus | 10 222 | 6 mo | ICD-9 401-405 | > 40 | ACE, BB, CCB, diuretic | 4 mo that AHT | Visits for 6-mo observation period | All new courses AHT |
| Monane et al (1997), New Jersey Medicaid Medicare | 8643 | 1 y | Hospital discharge only | 65–99, means 75.6 (SD 8.1) | Any AHT ≥ 1-mo supply | 12 mo any AHT; new only | Active use; at least 1 claim each 4 mo | Hospital, nursing home etc patients excluded |
| Rizzo and Simons (1997) Pennsylvania Medicaid | 7211 | 1 y | ICD-9 401, 401.1.401.9 | Mean 59.4 (SD 13.9) | ACE, BB, CCB, diuretic Monotherapy ≥ 1-mo supply | Not identified | Continuous eligibility | Nursing home excluded random sample selected |
| Okano et al (1997), US Dept Defense USPDP | 771 | 1 y | No | 20–49 | ACE, CCB | 6 mo selected AHT; new only | Continuous enrolment claims at start and end | 771/5947 enrolled continuously |
| Bloom (1998) Merck-Medco managed care | 21723 | 1 y | No | 35–71, mean 56 | ACE, BB, CCB, thiazide, AT2 monotherapy | 12 mo any AHT; new only | Not stated; dropouts considered to have stopped? | Exclude nitrates, antiarrhythmics, digoxin, warfarin, loop diuretics, and migraine medicines |
| Caro, Salas, et al (1999) Saskatchewan Health | 74181 | 5 y unless censored | ICD-9 401, 401.1.401.9 | > 40, median 65 | ACE, BB, CCB, diuretic, combination other (All 56 AHTs in Saskatchewan formulary) | 10 mo any AHT; new vs established | Patients observed minimum 1 y 5410 exclusions | Exclude other CVD, hepatic and renal disease, and pregnant women |
| Caro, Speckman, et al (1999) Saskatchewan Health | 22918 | 5 y unless censored | ICD-9 401, 401.1.401.9 | > 40, median 63 | ACE, BB, CCB, diuretic monotherapy | 10 mo any AHT; new only | Censoring after 6-mo observation | Exclude other CVD, hepatic and renal disease, and pregnant women |
| Benson et al (2000) US HMO | 7490 | 1 y | No | > 30 | Amlodipine, atenolol, HCTZ/triamterene, lisinopril, losartan, nifedipine, quinapril | 90 days any AHT; new only | Continuous eligibility | Discontinue in first year; min 30 days therapy; max 1200 per drug |
| Dezii (2000) US PBM | 3942 | 1 y | No | Not given | Lisinopril or enalapril + HCTZ Single tablet or 2 separate tablets | 6 mo any AHT; new only | Continuous eligibility; some claim at 1 y | None |
| Bourgalt et al (2001) Saskatchewan Health | 19501 | 5 y unless censored | Hospital discharge diagnosis only | 40–79, mean 60 | ACE, BB, CCB monotherapy or combination | 12 mo any AHT including diuretics, α-blockers, etc; new only | Included | Exclude CVD (ICD-9 402, 404, 410–416, 420–429, 745.4–746.9) and new only anticoagulants, loop diuretics, cardiac thyroid and migraine medicines |
| Conlin et al (2001) Merck-Medco managed care | 15175 | 4 y, same No cohort as Bloom | 35–71, mean 56 | ACE, BB, CCB, diuretic, AT2 monotherapy | 12 mo any AHT; new only | Continuous eligibility, 6548 excluded from Bloom cohort | Exclude nitrates, antiarrhythmics, digoxin, warfarin, loop diuretics, and migraine medicines | |
| Ren et al (2002) Boston Veteran’ Health | 1292 (59% response) | 2 y | Not stated | Mean 65.2 (SD 10.3) | Any AHT | Not identified | Observed 2 y complete | None |
| Degli Esposti E et al (2002) Ravenna LHU | 7312 | 3 y | No (hospital discharge only) | > 20 | ACE (C09A), BB (C07), CCB (C08), diuretic (C03), AT2 (C09C); monotherapy | 12 mo any AHT; new only | Leave/die excluded 478 | Exclude if < 7 days treatment |
| Marentette et al (2002) Saskatchewan Health | 46 458 | 5 y | ICD-9 401-405 | 1–95, mean 61 | ACE, BB, CCB, AT2, diuretic; initial class only; diuretic + AHT classified with other AHT Mixed classes ≥ 1 clas | 12 mo any AHT; new only | 4571 (9%) patients excluded as not observed entire period | Exclude patients receiving α-blockers, α-agonists, and vasodilators |
| Wang et al (2002), US HMO and Veterans’ Health | 496 (50% response) | 1 y | HT in previous year | > 40 | Any AHT | 180 days any AHT; new only | Continuous enrolment | Random sample eligible patients sent questionnaire |
| Hasford et al (2002), IMS Health Mediplus | 2416 | 1 y | New HT | Mean 61 (SD 12.7) | ACE, BB, CCB, diuretic, AT2 monotherapy | New-exclude if HT diagnosis previous year | Lost to follow-up classed discontinued | Patients matched to irbesartan group |
| Degli Esposti L et al (2002) Ravenna LHU | 16 783 | 1 y | No | > 20, mean 56.1 (SD 18.3) | ACE (C09A), BB (C07), CCB (C08), diuretic (C03), AT2 (C09C); monotherapy | 12 mo any AHT; new only | Leave/die excluded (660) | None |
| Wogen et al (2003) US PBM | 142 945 | 1 y | No | Mean 63.1 (SD 14.0) | Valsartan, amlodipine, lisinopril | 12 mo that class; new only | Continuous eligibility | None |
| Taylor and Shohelber (2003) US PBM | 5732 | 1 y | Yes | 18–64 | Amlodipine/benazepril or ACE + CCB | Not identified | Continuous eligibility | None |
| Degli Esposti et al (2004) Ravenna LHU | 14062 | 1 y | No | > 20 | ACE, BB, CCB, diuretic, AT2 monotherapy | 12 mo any AHT; new only | Leave/die excluded (817) | None |
Abbreviations: ACE, angiotensin-converting enzyme inhibitor; BB, β-blocker; CCB, calcium channel blocker; AT2, angiotensin-II antagonist; AHT, antihypertensive; HCTZ, hydrochlorothiazide; ICD, International Classification of Diseases; CVD, cardiovascular disease; HT, hypertension; min, minimum; max, maximum; mo, month; y, year.