Market share and costs of biologic therapies for inflammatory bowel disease in the USA

BACKGROUND

Real-world data quantifying the costs of increasing use of biologics in inflammatory bowel disease (IBD) are unknown.

AIM

To determine the outpatient IBD drug utilization trends, relative market share, and costs in the USA during a 9-year period.

METHODS

The Truven MarketScan^® Database was analysed for patients with Crohn's disease (CD) and ulcerative colitis (UC) during 2007-2015. National drug codes were used to identify prescription drugs; Healthcare Common Procedure Coding System J-codes were used to capture biologic out-patient infusions. Proportion of drug usage, relative market share and per-member per-year (PMPY) costs were analysed for biologics, immunomodulators, 5-ASAs and corticosteroids.

RESULTS

In 415 405 patients (188 842 CD; 195 183 UC; 31 380 indeterminate colitis; 54.67% female), utilization trends show a consistent rise in the market share of biologics during the 9-year study period. The proportion of patients using biologics increased from 21.8% to 43.8% for CD and 5.1%-16.2% for UC. This contrasts a small decrease in immunomodulator and 5-ASA use for CD and relative constancy of other classes including corticosteroids-only use as primary IBD medication from 2007 to 2015. The average biologic-taking patient accounted for $25 275 PMPY in 2007 and $36 051 PMPY in 2015. The average paediatric biologic-taking patient accounted for $23 616 PMPY in 2007 and $41 109 PMPY in 2015. In all patients, the share of costs for biologics increased from 72.9% in 2007 to 85.7% in 2015 (81.7% in 2007 to 94.9% in 2015 in paediatrics).

CONCLUSION

The vast majority of costs allocated to out-patient IBD medications in the USA is attributed to increasing use of biologic therapies despite the relative minority of biologic-taking patients.

Association between potentially inappropriate medications from the Beers criteria and the risk of unplanned hospitalization in elderly patients

BACKGROUND

Predisposition to adverse drug events with advancing age has led to the development of lists of potentially inappropriate medications (PIMs) to be avoided in the elderly, such as the Beers Criteria. The prevalence of Beers medications has been studied widely, but it is still unclear whether PIM use is predictive of adverse events in older people.

OBJECTIVES

To examine potential associations between exposure to PIMs from the general Beers list and unplanned hospitalizations in elderly Western Australians.

METHODS

Using an enhanced case-time-control design and conditional logistic regression applied to the pharmaceutical claims and other linked health data of 251 305 Western Australians aged ≥65 years (1993-2005), odds ratios for unplanned hospitalization were obtained, from which attributable fractions, number and proportion of hospitalizations associated with drug exposure were derived.

RESULTS

Based on the health profiles of 383 150 hospitalized index subjects, overall PIM exposure was associated with an elevated risk of unplanned hospitalization (adjusted odds ratio = 1.18; 95% confidence interval = 1.15-1.21), this estimated risk increasing with the number of different PIMs and PIM quantity taken. Fifteen percent of unplanned hospitalizations in exposed index subjects (1980 per year) were attributed to PIM exposure. Patients taking meperidine (pethidine), nitrofurantoin, promethazine, indomethacin, and thioridazine appeared to be at particularly high risk of unplanned hospitalization, whereas temazepam, oxazepam, diazepam, digoxin, amiodarone, ferrous sulfate, and naproxen were attributed the greatest numbers of unplanned hospitalizations.

CONCLUSIONS

Due caution prescribing Beers medications in the elderly seems justified, paying particular attention to PIMs listed above and to the concurrent use of multiple PIMs. Our results also support the retention of specific medications on PIM lists in future developments.

Use of case-time-control design in pharmacovigilance applications: exploration with high-risk medications and unplanned hospital admissions in the Western Australian elderly

PURPOSE

To use a case-time-control design to derive preliminary estimates of unplanned hospitalisations attributable to suspected high-risk medications in elderly Western Australians.

METHODS

Using pharmaceutical claims linked to inpatient and other health records, the study applied a case-time-control design and conditional logistic regression to estimate odds ratios (ORs) for unplanned hospital admissions associated with anticoagulants, antirheumatics, opioids, corticosteroids and four major groups of cardiovascular drugs. Attributable fractions (AFs) were derived from the ORs to estimate the number and proportion of admissions associated with drug exposure. Results were compared with those obtained from a more conventional method using International Classification of Diseases (ICD) external cause codes to identify admissions related to adverse drug events.

RESULTS

The study involved 1 899 699 index hospital admissions. Six of the eight drug groups were associated with an increased risk of unplanned hospitalisation, opioids (adjusted OR = 1.81, 95%CI 1.75-1.88; AF = 44.9%) and corticosteroids (1.48, 1.42-1.54; 32.2%) linked with the highest risks. For all six, the estimated number of hospitalisations attributed to the medication in the exposed was higher (two to 31-fold) when derived from the case-time-control design compared with identification from ICD codes.

CONCLUSIONS

This study provides an alternative approach for identifying potentially harmful medications and suggests that the use of ICD external causes may underestimate adverse drug events. It takes drug exposure into account, can be applied to individual medications and may overcome under-reporting issues associated with conventional methods. The approach shows great potential as part of a post-marketing pharmacovigilance monitoring system in Australia and elsewhere.