The study investigated the effect of various generic alendronate costs on the cost-effectiveness of osteoporosis screening and treatment in women aged 65 years and older. The authors concluded that osteoporosis screening followed by alendronate treatment provided value-for-money across a wide range of alendronate costs compared with no screening and alendronate treatment offered only after an osteoporotic fracture. The analysis considered a wide range of scenarios. The authors’ conclusions appear robust.

Cost-utility analysis

The study investigated the effect of various generic alendronate costs on the cost-effectiveness of osteoporosis screening and treatment in women aged 65 years and older.

Osteoporosis screening followed by alendronate treatment (70mg once weekly for five years) was compared with no screening and alendronate treatment offered only after an osteoporotic fracture.

Women were screened using dual-energy x-ray absorptiometry of the femoral neck and lumbar spine. Women who tested positive (T-score of -2.5 or lower at either site) were offered alendronate treatment; those who tested negative received usual care only (calcium and vitamin D).

USA/primary care.

Analytical approach:

The analysis was based on a Monte Carlo micro-simulation model of the two osteoporosis management strategies. A lifetime horizon was used. The perspective of the analysis was not explicitly reported.

Effectiveness data:

A selective approach appears to have been used to identify relevant sources of data. Treatment effect and rate of adverse events for alendronate were from clinical trials and meta-analyses. The baseline risk of fracture for the patient population was taken from the Study of Osteoporotic Fractures (SOF; an observational study). Other epidemiological data were taken from the National Health and Nutrition Examination Survey (NHANES) and other published sources. Fracture rates were key inputs of the model.

Monetary benefit and utility valuations:

Utility estimates were taken from published sources (details not given).

Measure of benefit:

Quality-adjusted life-years (QALYs) were used as the summary benefit measure and were discounted at annual rate of 3%.

Cost data:

The costs included dual-energy x-ray absorptiometry screening, alendronate therapy, fracture treatment, physician visits, nursing home residence, and alendronate-related adverse events. Data on costs and quantities of resources used came from various sources whose methodological characteristics were not reported. Various prices of alendronate were considered. Costs were in US $. The price year was 2010. A 3% annual discount rate was applied.

Analysis of uncertainty:

One-way sensitivity analyses were carried out varying key inputs (costs, discount rate, fracture risks, and probability of nursing home admission) and using alternative assumptions. A probabilistic sensitivity analysis was performed to evaluate the impact of joint input parameter uncertainty.

The alendronate treatment strategy gave greater health benefits (10.6 additional quality-adjusted life-days) and cost-savings up to an alendronate price of $200 (price in the USA at the time of the study was $84), resulting in a dominant strategy. The incremental cost per QALY gained with alendronate over no screening/treatment was $712 at a drug cost of $400, $7,307 at a drug cost of $600, and $13,902 at a drug cost of $800.

The cost-effectiveness of alendronate held in the sensitivity analyses, even if it was no longer cost-saving in several scenarios. At a cost-effectiveness threshold of $50,000 per QALY gained, alendronate remained the preferred strategy regardless of the drug cost. The stochastic analysis showed that the probability of alendronate being cost-effective was 95% at a drug cost of $100 and 84% at a drug cost of $800.

The authors concluded that osteoporosis screening followed by alendronate treatment provided value-for-money across a wide range of alendronate costs.

Interventions:

The selection of the comparators was appropriate. The choice of no screening as the background comparator allowed the assessment of the additional value of the screening/treatment branch of the model. The authors stated that other oral bisphosphonates (like risedronate) might have a similar cost-effectiveness profile.

Effectiveness/benefits:

Although clinical data were not retrieved by means of a systematic review of the literature, valid sources appeared to have been selected. Treatment effect and safety data for alendronate were taken from clinical trials and meta-analyses that should ensure high internal validity. The baseline fracture risk was obtained from an observational study presumably conducted in the authors’ setting which was representative of the patient population under analysis. Extensive sensitivity analyses on all clinical parameters were conducted.

QALYs were an appropriate benefit measure, as they captured the impact of the treatment on disease for both survival and quality of life. Limited information was provided on the derivation of utility valuation, which would have been useful to judge the validity of sources and instruments used.

Costs:

The costs reflected the perspective of the third-party payer, but this was not explicitly stated by the authors. The economic analysis was not extensively reported, as no clear information on data sources was given. The cost of dual-energy x-ray absorptiometry was reported and the cost of alendronate was varied (from $20 to $800) to assess its impact on cost-effectiveness results. Other costs were not reported. Reflation exercises in other time periods were feasible as the price year was explicitly reported.

Analysis and results:

An incremental approach was appropriately used to synthesise costs and benefits; the estimates were clearly reported. A simplified schematic of the model was provided to represent the key transitions of women over time. The authors stated that model outcomes (fracture and life expectancy predictions) were validated using published US data. Both deterministic and probabilistic sensitivity analyses were performed to investigate uncertainty underlying selected inputs. The results of the sensitivity analyses were clearly reported. The authors acknowledged some limitations of their analysis, such as the exclusion of some potential adverse events for alendronate or the possibility of lower compliance to treatment than they assumed. The study results might be relevant for other settings with similar relative prices and baseline fracture risk.

Concluding remarks:

The analysis considered a wide range of scenarios. The authors’ conclusions appear robust.

The study was supported by a grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases, a grant from the National Center for Research Resources (a component of the National Institutes of Health, NIH) and National Institutes of Health Roadmap for Medical Research, and a grant from the National Institute of Diabetes and Digestive and Kidney Diseases, USA.