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1.  Completeness of prescription information in US commercial claims databases 
Pharmacy commercial claims databases are widely used for pharmacoepidemiologic research. However, concerns have been raised that these databases may not fully capture claims for generic medication as a result of patients filling outside the context of their insurance. This has implications for many research activities and quality improvement programs. We sought to estimate the percentage of missing drug claims in US commercial claims data using a novel design.
Using a large US commercial insurance database, we examined the completeness of warfarin prescription claims among patients with atrial fibrillation receiving regular medical follow-up and testing to manage warfarin dosing. We examined 14 different 6-month cross sections. Each cross section was treated independently to identify patients with at least 2 outpatient diagnoses of atrial fibrillation, 2 international normalized ratio tests, and 1 pharmacy claim. Trends in the percentage of patients with prescription claims for generic and branded warfarin were compared by year and 6-month periods using chi-square tests and generalized linear models adjusting for patient characteristics.
Out of 111,170 patients, the percentage of patients with any warfarin drug decreased slightly from 91.7% (95% CI: 91.0, 92.4) in early 2003 to 87.1% (95% CI: 86.7-87.6) in late 2009 (χ2=93.8, p<0.0001). Over the same interval, the proportion of patients with generic warfarin exposure appearing increased significantly, while the proportion of patients with branded warfarin exposure decreased significantly.
Our study supports the possibility that some prescriptions may not be captured in US commercial insurance databases.
PMCID: PMC4012425  PMID: 23696101
generic drugs; claims data; data quality
2.  Osteoporosis medication adherence: Physician perceptions vs. patients' utilization. 
Bone  2013;55(1):1-6.
Few data are available on physician perceptions of osteoporosis medication adherence. This study compared physician-estimated medication adherence with adherence calculated from their patients' pharmacy claims. Women aged ≥45 years, with an osteoporosis-related pharmacy claim between January 1, 2005 and August 31, 2008, and continuous coverage for ≥12 months before and after first (index) claim, were identified from a commercial health plan population. Prescribing physicians treating ≥5 of these patients were invited to complete a survey on their perception of medication adherence and factors affecting adherence in their patients. Pharmacy claims-based medication possession ratio (MPR) was calculated for the 12-month post-index period for each patient. Physicians who overestimated the percentage of adherent (MPR ≥0.8) patients by ≥10 points were considered “optimistic”. Logistic regression assessed physician characteristics associated with optimistic perception of adherence. A total of 376 (17.2%) physicians responded to the survey; 62.0% were male, 58.2% were aged 45 to 60 years, 55.3% had ≥20 years of practice, and 35.4% practiced in an academic setting. Participating physicians prescribed osteoporosis medications for 2748 patients with claims data (mean [SD] age of 62.0 [10.6] years). On average, physicians estimated 67.2% of their patients to be adherent; however, only 40% of patients were actually adherent based on pharmacy data. Optimistic physicians (73.4%) estimated 71.9% of patients to be adherent while only 32.2% of their patients were adherent based on claims data. Physicians in academic settings were more likely to be optimistic than community-based physicians (odds ratio 1.69, 95% CI: 1.01, 2.85). Overestimation of medication adherence may impede physicians' ability to provide high quality care for their osteoporosis patients.
PMCID: PMC3777338  PMID: 23502042
Postmenopausal osteoporosis; Adherence; Compliance; Persistence; Bisphosphonates
3.  Discontinuation and reinitiation patterns of osteoporosis treatment among commercially insured postmenopausal women 
Poor adherence to chronic medications is common and compromises medication effectiveness. We sought to describe longitudinal patterns of osteoporosis medication use.
Study design
This was a retrospective observational cohort study using 2005–2009 data from a large, commercially insured population.
Patients were women aged ≥55 years initiating osteoporosis therapy who had a ≥12-month (baseline) period with no osteoporosis therapy claims preceding initiation, and ≥24 months follow-up after therapy initiation. Discontinuation was defined as a gap >60 days (varied in sensitivity analyses) in prescription claims. Reinitiation was defined as a prescription claim for the same or different osteoporosis therapy following the therapy gap. Discontinuation and reinitiation patterns were described using Kaplan–Meier analysis. Multivariable Cox regression assessed the impact of baseline factors on reinitiation.
Of the 92,839 patients, 45%, 58%, and 70% discontinued therapy at 6, 12, and 24 months, respectively, following initiation. Of the discontinuers, 46% reinitiated therapy, with the majority doing so within 6 months of discontinuation. Women were less likely to reinitiate therapy if they were older (P < 0.0001) or were hospitalized during baseline (P = 0.0007). Women who discontinued treatment early (<6 months) following initiation were less likely to reinitiate (P < 0.0001) and remained on therapy for shorter periods following reinitiation. Depending on the available observation time, the median time on therapy following reinitiation was 58–193 days. Study findings did not change appreciably in sensitivity analyses.
Many patients stop and restart treatment for osteoporosis. A better understanding of determinants of treatment stopping and restarting could inform adherence improvement efforts.
PMCID: PMC3825671  PMID: 24235846
bisphosphonates; persistence; adherence; osteoporosis; therapy utilization
4.  Accuracy and Cost-Effectiveness of Cervical Cancer Screening by High-Risk HPV DNA Testing of Self-Collected Vaginal Samples 
Estimate the accuracy and cost-effectiveness of cervical cancer screening strategies based on high-risk HPV DNA testing of self-collected vaginal samples.
Materials and Methods
A subset of 1,665 women (18-50 years of age) participating in a cervical cancer screening study were screened by liquid-based cytology and by high-risk HPV DNA testing of both self-collected vaginal swab samples and clinician-collected cervical samples. Women with positive/abnormal screening test results and a subset of women with negative screening test results were triaged to colposcopy. Based on individual and combined test results, five screening strategies were defined. Estimates of sensitivity and specificity for cervical intraepithelial neoplasia grade 2 or worse were calculated and a Markov model was used to estimate the incremental cost-effectiveness ratios (ICERs) for each strategy.
Compared to cytology-based screening, high-risk HPV DNA testing of self-collected vaginal samples was more sensitive (68%, 95%CI=58%-78% versus 85%, 95%CI=76%-94%) but less specific (89%, 95%CI=86%-91% versus 73%, 95%CI=67%-79%). A strategy of high-risk HPV DNA testing of self-collected vaginal samples followed by cytology triage of HPV positive women, was comparably sensitive (75%, 95%CI=64%-86%) and specific (88%, 95%CI=85%-92%) to cytology-based screening. In-home self-collection for high-risk HPV DNA detection followed by in-clinic cytology triage had a slightly lower lifetime cost and a slightly higher quality-adjusted life expectancy than did cytology-based screening (ICER of triennial screening compared to no screening was $9,871/QALY and $12,878/QALY, respectively).
Triennial screening by high-risk HPV DNA testing of in-home, self-collected vaginal samples followed by in-clinic cytology triage was cost-effective.
PMCID: PMC2898894  PMID: 20592553
cervical cancer; screening; hpv; self-collect; cost-effectiveness
5.  Development and Evaluation of a Liquid Bead Microarray Assay for Genotyping Genital Human Papillomaviruses▿ †  
Journal of Clinical Microbiology  2009;47(3):547-553.
We developed a liquid bead microarray (LBMA) assay for genotyping genital human papillomaviruses (HPVs) based on the MY09-MY11-HMB01 PCR system and the reverse line blot (RLB) assay probe sequences. Using individual HPV plasmids, we were able to detect as few as 50 copies per reaction. In two separate retrospective studies, the LBMA assay was compared to the RLB assay and to the Hybrid Capture II (hc2) assay. Testing was performed without knowledge of other assay results. In the first study, 614 cervical swab samples (enriched for HPV infection) from 160 young women were tested for HPV DNA, and 360 (74.8%) type-specific HPV infections were detected by both assays, 71 (14.8%) by the LBMA assay only, and 50 (10.4%) by the RLB assay only. Type-specific agreement for the two assays was excellent (99.1%; kappa = 0.85; 95% confidence interval [95% CI], 0.82 to 0.88). Samples with discrepant LBMA and RLB test results tended to have low viral loads by a quantitative type-specific PCR assay. In the second study, cervical swab samples from 452 women (including 54 women with histologically confirmed cervical-intraepithelial neoplasia grade 2 or worse [≥CIN2]) were tested initially by the hc2 and subsequently by the LBMA assay. The estimated sensitivities for ≥CIN2 were similar for the LBMA and hc2 assays (98.4% [95% CI, 95.0 to 100%] and 95.6% [95% CI, 89.2 to 100%], respectively). The percentages of negative results among 398 women without ≥CIN2 were similar for the LBMA and hc2 assays (45% and 50%, respectively). The repeat test reproducibility for 100 samples was 99.1% (kappa = 0.92; 95% CI, 0.90 to 0.95). We conclude that the new LBMA assay will be useful for clinical and epidemiological research.
PMCID: PMC2650937  PMID: 19144800

Results 1-5 (5)