Table 2.
Summary of methodological characteristics of cohort studies.
| [Briesacher et al. 2007] | [Caro et al. 2004] | [Curtis et al. 2008b] | [Gallagher et al. 2008] | [Hoer et al. 2009] | [Huybrechts et al. 2006] | [Penning-van Beest et al. 2008] | [Sheehy et al. 2009] | [Siris et al. 2006] | |
|---|---|---|---|---|---|---|---|---|---|
| Treatment | ALD, RSD | ALD, CCT, ETD, RSD, HT | ALD, RSD, IBD | ALD, RSD | ALD, RSD, ETD | ALD, RSD, HT | ALD, RSD | ALD, RSD | ALD, RSD |
| Evaluated drug class separately | NA | No | NA | NA | NA | No | NA | NA | NA |
| Baseline (lookback) period |
1 year | NP | 6 months | 1 year (new user) 0.25–1 year (covariates) | 6 months (new user) 1 year (covariates) | Variable | 1 year | 2 years (new user, prior fx and drug covariates) 1 year (other covariates) | 6 months |
| New users (drug) | Yes (BP) | No | Yes (BP) | Yes (ALD, RSD) | Yes (BP) | No | Yes (All OP drugs) | Yes (weekly BP) | Yes (BP) |
| Allowed switching | Yes | NP | Yes (between BPs; others censored) | NP | Yes | Yes (any) | NP | NP | NP |
| >1 Rx needed | No | No | No | Sub-analysis for 2 + Rxs | No | No | Sub-analysis for 2 + Rxs | No | No |
| Immeasurable time | NP | Assumed 100% compliance |
NP | NP | NP | Assumed 100% compliance |
NP | NP | NP |
| Compliance measure | PDC | MPR | MPR | MPR | MPR | MPR | PDC | MPR | MPR |
| How compliance quantified (1 = primary 2 = secondary) | 0–19%, 20–39%; 40–59%; 60–79%; 80–100% | 1) ≥80% 2) <50%, 50–80%, 80–90%, >90% |
1) ≥80% 2) <50%, 50–80%, ≥80% |
Not Stated: linear regression with 10 subgroups | ≥80% | 1)≥80% 2)<50%, 50–80%, 80–90%, >90% |
1)≥80% 2)<20, 20– 49, 50–69, 70–89, ≥90% |
≥80% | 1) ≥80% 2) Continuous range (0–100%) |
| How compliance measured (1 = primary 2 = secondary) | Time Varying (1 year) | 1) Entire follow-up 2) Ascertainment Period (6/12 months) | 1) Time Varying (90 days) 2) Entire Follow-up |
Entire follow-up | Entire follow-up | Entire follow-up | Time varying (90 days) | Entire follow-up | Entire follow-up |
| Start of fracture identification | Fx after 1 year | Fx after 180 days | Fx after 90 days | Any | Any | Fx after 180 days | Fx after 182 days | Any | Any |
| Length of follow-up to identify fracture risk | Minimum 2 yrs; 60,208 person-years follow-up | 22,753 person-years; mean 2 years | Variable | Mean 2.32 years | Minimum 180 days (82% had 1 + year, 47% 2 + years) | 63,438 person-years; mean of 1.7 years | 22,484 person-years | 1 year | 2 years |
| Minimum confounders for adjustment | |||||||||
| Age | Yes | Yes | Yes | Yesc | Yes | Yes | Yes | Yes | Yes |
| Sex | Yes | Yesa | Yes | Yesc | Yes | Yesa | Yesa | Yes | Yesa |
| Prior fracture | Yes | Yes | Yes | Yesc | Yes | Yes | Yes | Yesb | Yes |
| Comorbidity/drug score |
Yes | No | Yes | Yesc | No | No | No | No | No |
ALD, alendronate; BMD, bone mineral density; BP, bisphosphonates; CCT, calcitonin; ETD, etidronate; Fx, fracture; GCC, glucocorticoids; HT, hormone therapy; IBD, ibandronate; MPR, medication possession ratio; NA, not applicable; NP, data not provided; OP, osteoporosis; PDC, proportion of days covered; RAL, raloxifene; RSD, risedronate; Rx, prescription.
a
Study only evaluated females.
b
Study separated cohorts into those with and without a prior fracture (primary and secondary prevention).
c
Confounder considered –however it is unclear what was included in the final adjusted analysis.