Table 2.
Outcome definitions and rates
| Reference | Outcomes | Continuing rates | Switching rates |
|---|---|---|---|
| Jones et al (1995) | Continuation = still taking initial therapy (class); not continuing if gap > 60 days | 6 mo (calculated monthly); diuretic 41%, BB 49%, CCB 41%, ACE 45% | 6 mo: diuretic 49%, BB 43%, CCB 52%, ACE 48% |
| Switch = stop initial therapy and prescribed AHT from different class | |||
| Monane et al (1997) | Compliant = PDC > 80% any AHT | Calculated at 1 y; 20% patients compliant | |
| Switches included as compliant | |||
| Rizzo and Simons (1997) | Compliance = PDC averaged over all AHT classes | Calculated at 1 y: overall estimates; diuretic 5%, BB 29%, CCB 35%, ACE 35% | |
| Switches included as compliant | |||
| Okano et al (1997) | Continuous use = PDC > 80% on any AHT | At 1 y: continuous use any AHT: ACE 55.5%, CCB 49.4%; initial therapy only (including dose changes) ACE 35.4%, CCB 26.6% | 1 y switches/additions of therapy; ACE 20.1%, CCB 22.8% |
| Switches included as continuous use; tabulated for continuous users at 1 y | |||
| Bloom (1998) | Persistent = refill initial prescription at 12 (+ 3) mo | Calculated at 1 y; diuretic 38%, BB 43%, CCB 50%, ACE 58% AT2 64% | 1 y; diuretic 6%, BB 7%, CCB 9%, ACE 9%, AT2 7% |
| Switch is change of AHT class | |||
| Caro, Salas, et al (1999) | Persistent (+ cumulative rates) = last prescribed | 1 y; established 97%, new 78% | |
| AHT covers period until end of observation, allowing for previous accumulation; switches included as persistent | |||
| Caro, Speckman et al (1999) | Persistent (+ cumulative rates) = last prescribed | 6 mo; diuretic 80%, BB 85%, CCB 86%, ACE 89% | |
| AHT covers period until end of observation, allowing for previous accumulation; switches included as persistent | |||
| Benson et al (2000) | Duration = date last prescription + days covered by this – start date. Discontinued if initial AHT not available > 30 days and no AHT within 90 days of end | Median duration: 90 days all drugs except HCTZ comb. 80 days. | |
| Note: only patients who discontinued AHTs included | |||
| Dezii (2000) | Persistent (monthly) = initial AHT without missing > 3 prescriptions in year observed | At 1 y (calculated monthly); lisinopril/HCTZ 1 tab 68.7%, 2 tabs 57.8% | |
| Not persistent if failing to renew 3 prescriptions during year | |||
| Bourgalt et al (2001) | Time to first modification = any change of initial therapy (drug titration allowed) | 1 y no modification 33.8%; 5 y no modification 11.5%; BB 7.9%, CCB 9.3%, ACE 13.1%, combination 22.3% | 1st modification: addition 20.1%, switch 14.3%, interruption (gap > 90 days) 31.5%, discontinue 22.6% |
| Switch = change therapy (class) and stop initial AHT; maximum gap 90 days | |||
| Conlin et al (2001) | Persistent = refill initial AHT at 12, 24, 36, 48 (+3) mo | At 1 y (calculated yearly); diuretic 20.8%, BB 45.6% CCB 54.1%, ACE 60.7% AT2 67.4% | 1 y; diuretic 18.8%, BB 6.4%, CCB 9.8%, ACE 9.6%, AT2 8.0% |
| Switch = no initial AHT and change AHT clas in follow-up intervals | |||
| Ren et al (2002) | Compliance rates = PDC any AHT excluding last prescription | At 2 y; compliant 72.8% | |
| Compliant = PDC > 80% not including last prescription | |||
| Degli Esposti E et al (2002) | Persistence = duration first–last prescription any AHt; continuing if > 1 AHT each year | 3 y; 57.9% continue | Restart 7.6%; ≥ 2 AHTs 1st and 3rd year and < 2 AHTs 2nd year |
| Switches include continuers | |||
| Marentette et al (2002) | Persistence = prescription from initial class only within previous 90 days at 4 time points | Calculated at days 180, 360, 540, 720; 360 days overall 63.8%; 180 days diuretic 52.0%, BB 67.2%, CCB 69.8%, ACE 75.1%, AT2 87.8% | 180 days; mixed 79.7% |
| Switches included in “mixed” class | |||
| Wang et al (2002) | Compliance = PDC any AHT tertiles (50%, 80%) | Calculated at 1 y; PDC > 80% in 29% of patients | |
| Switches included as compliant | |||
| Hasford et al (2002) | Persistence = initially prescribed monotherapy; discontinue = gap > 30 days | 1 y overall 46.8%; diuretic 34.4%, BB 49.7%, CCB 43.6%, ACE 42.0%, other AT2 51.3%, irbesartan 60.8% | 1 y; add 23.8%, change 12.9% |
| Switch = any change from initial monotherapy Duration on initially prescribed monotherapy (until switch/discontinue/end observation) | |||
| Degli Esposti L et al (2002) | Persistence = continue with initial therapy after 9 mo (continuers/switchers) | 1 y overall 26.9%; diuretic 23.1%, BB 30.9%, CCB 23.7%, ACE 30.7%, AT2 33.4% | 1 y overall 8.2%; diuretic 7.1%, BB 6.7%, CCB 7.6%, ACE 9.4%, AT2 24.6% |
| Duration any AHT time covered first-last prescription | |||
| Wogen et al (2003) | Persistence = remain on initial AHT no gap > 60 days | 1 y overall 54%; valsartan 63%, amlodipine 53%, lisinopril 50% | |
| Switches not analyzed. Duration = last prescription date – first prescription date (initial AHT) | |||
| Taylor and Shoheiber (2003) | Adherence = PDC excluding last prescription 2 tablets: time is first prescription second drug – last prescription last drug (ie, sequential/combined) | Calculated at last prescription observed: combination 80.8%, ACE + CCB 73.2% | |
| Degli Esposti et al (2004) | Persistence = continue with initial therapy after 9 mo (continuers/switchers) | 1 y overall 30.9%; diuretic 25.9%, BB 36.9%, CCB 26.9%, ACE 32.2%, AT2 41.7% | 1 y overall 8.8%; diuretic 7.3%, BB 6.5%, CCB 8.6%, ACE 10.6%, AT2 13.2% |
| Duration any AHT time covered first–last prescription |
Abbreviations: ACE, angiotensin-converting enzyme inhibitor; BB, β-blocker; CCB, calcium channel blocker; AT2, angiotensin-II antagonist; AHT, antihypertensive; HCTZ, hydrochlorothiazide; PDC, proportion of days covered; mo, month; y, year.