Fracture definitions in observational osteoporosis drug effects studies that leverage healthcare administrative (claims) data: a scoping review

Healthcare administrative (claims) data are commonly utilized to estimate drug effects. We identified considerable heterogeneity in fracture outcome definitions in a scoping review of 57 studies that estimated osteoporosis drug effects on fracture risk. Better understanding of the impact of different fracture definitions on study results is needed.

PURPOSE

Healthcare administrative (claims) data are frequently used to estimate the real-world effects of drugs. Fracture incidence is a common outcome of osteoporosis drug studies. We aimed to describe how fractures are defined in studies that use claims data.

METHODS

We searched MEDLINE (Ovid), Embase (Ovid), CINAHL (EBSCO), and gray literature for studies published in English between 2000 and 2020 that estimated fracture effectiveness (hip, humerus, radius/ulna, vertebra) or safety (atypical fracture of the femur, AFF) of osteoporosis drugs using claims data in Canada and the USA. Literature searches, screening and data abstraction were completed independently by two reviewers.

RESULTS

We identified 57 eligible studies (52 effectiveness, 3 safety, 2 both). Hip fracture was the most common fracture site studied (93%), followed by humerus (66%), radius/ulna (59%), vertebra (61%), and AFF (9%). Half (n = 29) of the studies did not indicate specific data sources, codes, or cite a validation paper. Of the papers with sufficient detail, heterogeneity in fracture definitions was common. The most common definition within each fracture site was used by less than half of the studies that examined effectiveness (12 definitions in 29 hip fracture papers, 8 definitions in 17 humerus papers, 8 definitions in 13 radius/ulna papers, 9 definitions in 15 vertebra papers), and 3 definitions among 4 AFF papers.

CONCLUSION

There is ambiguity and heterogeneity in fracture outcome definitions in studies that leverage claims data. Better transparency in outcome reporting is needed. Future exploration of how fracture definitions impact study results is warranted.

Estimating chronic hepatitis C prognosis using transient elastography-based liver stiffness: A systematic review and meta-analysis

Chronic hepatitis C (CHC) is a leading cause of hepatic fibrosis and cirrhosis. The level of fibrosis is traditionally established by histology, and prognosis is estimated using fibrosis progression rates (FPRs; annual probability of progressing across histological stages). However, newer noninvasive alternatives are quickly replacing biopsy. One alternative, transient elastography (TE), quantifies fibrosis by measuring liver stiffness (LSM). Given these developments, the purpose of this study was (i) to estimate prognosis in treatment-naïve CHC patients using TE-based liver stiffness progression rates (LSPR) as an alternative to FPRs and (ii) to compare consistency between LSPRs and FPRs. A systematic literature search was performed using multiple databases (January 1990 to February 2016). LSPRs were calculated using either a direct method (given the difference in serial LSMs and time elapsed) or an indirect method given a single LSM and the estimated duration of infection and pooled using random-effects meta-analyses. For validation purposes, FPRs were also estimated. Heterogeneity was explored by random-effects meta-regression. Twenty-seven studies reporting on 39 groups of patients (N = 5874) were identified with 35 groups allowing for indirect and 8 for direct estimation of LSPR. The majority (~58%) of patients were HIV/HCV-coinfected. The estimated time-to-cirrhosis based on TE vs biopsy was 39 and 38 years, respectively. In univariate meta-regressions, male sex and HIV were positively and age at assessment, negatively associated with LSPRs. Noninvasive prognosis of HCV is consistent with FPRs in predicting time-to-cirrhosis, but more longitudinal studies of liver stiffness are needed to obtain refined estimates.

Proportion of osteoporotic post-menopausal women at increased risk for upper GI adverse events associated with bisphosphonate therapy

Background- The bisphosphonate alendronate has been associated with higher rates of adverse oesophageal effects when used in the community setting compared to what was observed in the clinical trials. Patients with a history of gastroesophageal problems or who are concurrently using an NSAID therapy may be at increased risk for the gastroesophageal problems associated with alendronate use. This study assesses the proportion of post-menopausal women in the community with osteoporosis that are at increased risk for gastroesophageal adverse effects associated with alendronate.Methods- The administrative database for the Quebec government drug benefit program was used to identify a cohort of 5400 post menopausal women aged 65 years or older who were using the bisphosphonate etidronate for the treatment of osteoporosis. Patients were evaluated for the presence of either risk factor, chronic GI drug therapy use (a marker for prior gastroesophageal problems) or chronic NSAID use.Findings- 31% of women taking etidronate were also chronically using GI drug therapies and 50% were using NSAIDs; 18% of the women were using all three drugs.Interpretation- Many osteoporosis patients in the community setting who are candidates for bisphosphonate therapy might be considered at increased risk for alendronate's gastroesophageal adverse effects. This may account for differences in pre-marketing and postmarketing event rates. Copyright (c) 2000 John Wiley & Sons, Ltd.

Use of instrumental variables in the analysis of generalized linear models in the presence of unmeasured confounding with applications to epidemiological research

A major, often unstated, concern of researchers carrying out epidemiological studies of medical therapy is the potential impact on validity if estimates of treatment are biased due to unmeasured confounders. One technique for obtaining consistent estimates of treatment effects in the presence of unmeasured confounders is instrumental variables analysis (IVA). This technique has been well developed in the econometrics literature and is being increasingly used in epidemiological studies. However, the approach to IVA that is most commonly used in such studies is based on linear models, while many epidemiological applications make use of non-linear models, specifically generalized linear models (GLMs) such as logistic or Poisson regression. Here we present a simple method for applying IVA within the class of GLMs using the generalized method of moments approach. We explore some of the theoretical properties of the method and illustrate its use within both a simulation example and an epidemiological study where unmeasured confounding is suspected to be present. We estimate the effects of beta-blocker therapy on one-year all-cause mortality after an incident hospitalization for heart failure, in the absence of data describing disease severity, which is believed to be a confounder.

Impact of antibiotic administrative restrictions on trends in antibiotic resistance

CONTEXT

In March 2001, in response to concerns about increasing resistance to fluoroquinolone (FQ) antibiotics, the Ontario Drug Benefit (ODB) program limited reimbursement of FQs to ODB beneficiaries defined as high risk or in whom other therapies are not tolerated.

OBJECTIVE

To analyze the impact of the limited use (LU) policy changes on antibiotic resistance rates in Ontario, focussing on community-acquired pathogens.

DESIGN

Ontario data submitted to the Canadian Bacterial Surveillance Network (CBSN) between January 1, 1998 and June 30, 2002 were analyzed for rates of resistance in various pathogen-antibiotic combinations. The effect of the LU policy on the level and rate of change of antibiotic resistance was estimated using time series models.

RESULTS

Resistance rates for S. pneumoniae were 10-12% for penicillin, erythromycin and trimethoprim sulfamethoxazole (TMP/SMX) and less than 3% for amoxicillin and all three FQs tested. There was a statistically significant increasing trend in resistance rates of S. pneumoniae to amoxicillin and levofloxacin throughout the study period. Antibiotic resistance of S. pneumoniae to ciprofloxacin indicated a statistically significant decreasing trend over the study period with a statistically significant increase in the level of antibiotic resistance at the time of the LU policy implementation. No other indication of any statistically significant decrease in resistance rates associated with the LU policy was found.

CONCLUSIONS

Although no direct cause and effect can be proven with these observational data, there is no evidence that the limited use policy to restrict fluoroquinolones decreased antibiotic resistance in any of the pathogen-antibiotic combinations tested.

Impact of antibiotic administrative restrictions on trends in antibiotic resistance

CONTEXT

In March 2001, in response to concerns about increasing resistance to fluoroquinolone (FQ) antibiotics, the Ontario Drug Benefit (ODB) program limited reimbursement of FQs to ODB beneficiaries defined as high risk or in whom other therapies are not tolerated.

OBJECTIVE

To analyze the impact of the limited use (LU) policy changes on antibiotic resistance rates in Ontario, focussing on community-acquired pathogens.

DESIGN

Ontario data submitted to the Canadian Bacterial Surveillance Network (CBSN) between January 1, 1998 and June 30, 2002 were analyzed for rates of resistance in various pathogen-antibiotic combinations. The effect of the LU policy on the level and rate of change of antibiotic resistance was estimated using time series models.

RESULTS

Resistance rates for S. pneumoniae were 10-12% for penicillin, erythromycin and trimethoprim sulfamethoxazole (TMP/SMX) and less than 3% for amoxicillin and all three FQs tested. There was a statistically significant increasing trend in resistance rates of S. pneumoniae to amoxicillin and levofloxacin throughout the study period. Antibiotic resistance of S. pneumoniae to ciprofloxacin indicated a statistically significant decreasing trend over the study period with a statistically significant increase in the level of antibiotic resistance at the time of the LU policy implementation. No other indication of any statistically significant decrease in resistance rates associated with the LU policy was found.

CONCLUSIONS

Although no direct cause and effect can be proven with these observational data, there is no evidence that the limited use policy to restrict fluoroquinolones decreased antibiotic resistance in any of the pathogen-antibiotic combinations tested.

On the evaluation of drug benefits policy changes with longitudinal claims data: the policy maker's versus the clinician's perspective

Cost containment in pharmaceutical-benefit plans are often controversially debated for their potential of unintended consequences on health and overall expenditures. Thorough evaluations are needed but hypotheses and design considerations are complex. Our objective is to provide a structured framework for the evaluation of drug-benefit changes using longitudinal claims data. Differential cost sharing (DCS) will serve as a recent example. Benefit-plan managers are mainly interested in the overall performance of their plan. In a policy model, any observed policy-related effects may be compared with what would have happened had the intervention not been implemented by extrapolating the pre-policy trend from the same patients. These estimates will reflect the global consequences of the policy maker's decision. However, such estimates represent summary effects of benefits and harms, separately identifiable in those complying with the intended policy and those not complying. Results from a policy model apply only to a specific policy implementation and tend to underestimate effects when non-compliance is high. Clinical-decision makers and patients, by contrast, are interested in the consequences of patients' actual compliance to the policy. A clinical model assesses the effects of DCS depending on the actual treatment in contrast to the treatment intended by the policy. However, this model must sometimes make, unprovable assumptions about the appropriate control of selection factors. In conclusion, both policy and clinical models should be tested with a clear understanding of their perspectives, hypotheses, and interpretations, using quasi-experimental time-series designs to evaluate the effects of drug cost-containment policies.

Health Utilities Index Mark 3: evidence of construct validity for stroke and arthritis in a population health survey

BACKGROUND

The Health Utilities Index Mark 3 (HUI3) is a comprehensive, compact health status classification and health state preference system. The HUI3 system has been included in 4 Canadian population health surveys and numerous clinical trials.

OBJECTIVES

To evaluate the construct validity of the HUI3 for the measurement of health-related quality of life (HRQL) and attribute-specific morbidity in respondents to the 1990 Ontario Health Survey reported to have arthritis or stroke. The authors assessed (1) whether those with stroke, arthritis, and both conditions had lower HRQL scores than those with neither condition and (2) whether HUI3 detects morbidity in specific health attributes affected by arthritis and stroke. Stroke (but not arthritis) were expected to affect speech and cognition; arthritis (but not stroke) to affect pain; both to affect mobility, dexterity, and emotion; and neither to affect vision and hearing.

RESEARCH DESIGN

Linear regression models of HRQL and attribute-specific utilities were estimated as a function of 3 indicator variables of health problem (stroke only, arthritis only, both) and variables included to reduce confounding.

RESULTS

Subjects with stroke, arthritis, and both conditions had substantially lower HRQL than those with neither condition. Stroke subjects had greater morbidity in speech and cognition than arthritis subjects; somewhat surprisingly, pain morbidity was only slightly higher among arthritis subjects; neither condition affected vision or hearing. These associations were robust to various model specifications.

CONCLUSIONS

The HUI3 system appears valid for measuring health status and HRQL for stroke and arthritis in the context of a noninstitutionalized population health survey.

Cost analysis of dialysis treatments for end-stage renal disease (ESRD)

The cost of alternative dialysis modalities for the treatment of end-stage renal disease (ESRD) was evaluated, using a societal viewpoint, in a regional nephrology program in south-western Ontario. The dialysis treatments compared were hospital hemodialysis, home hemodialysis, self-care hemodialysis, and continuous ambulatory peritoneal dialysis (CAPD). The participants were all patients treated by the same dialysis modality for the fiscal year April 1990 to March 1991. Fully allocated costs are expressed in 1993 Canadian dollars. The average costs per patient year were $88,585 for hospital hemodialysis, $55,593 for self-care hemodialysis, $44,790 for CAPD, and $32,570 for home hemodialysis. The dialysis treatment costs were $54,929 for hospital hemodialysis, $43,313 for self-care hemodialysis, $31,918 for CAPD, and $26,048 for home hemodialysis. These data quantify the magnitude of the differences between fully-allocated costs among the dialysis modalities in a regional nephrology program in Canada. The methodology used in this economic analysis can be applied to programs which differ in structure and scale. The breakdown of dialysis treatment costs into overhead, support department, personnel, supplies, and medication identifies potential areas for cost reduction strategies.