Factors Associated with Celecoxib and Rofecoxib Utilization

An observational study of the discrediting of COX-2 NSAIDs in Australia: Vioxx or class effect?

Background

When a medicine such as rofecoxib (Vioxx) is withdrawn, or a whole class of medicines discredited such as the selective COX-2 inhibitors (COX-2s), follow-up of impacts at consumer level can be difficult and costly. The Australian Longitudinal Study on Women's Health provides a rare opportunity to examine individual consumer medicine use following a major discrediting event, the withdrawal of rofecoxib and issuing of safety warnings on the COX-2 class of medicines. The overall objective of this paper was to examine the impact of this discrediting event on dispensing of the COX-2 class of medicines, by describing medicine switching behaviours of older Australian women using rofecoxib in September 2004; the uptake of other COX-2s; and the characteristics of women who continued using a COX-2.

Methods

Participants were concessional beneficiary status women from the Older cohort (born 1921-26) of the Australian Longitudinal Study on Women's Health who consented to linkage to Pharmaceutical Benefits Scheme data, with at least one rofecoxib prescription dispensed in the 12 months before rofecoxib withdrawal. A prescription was defined as one dispensing occasion. Women were grouped by rofecoxib pattern of use: continuous (nine or more prescriptions dispensed in the 12 months prior to rofecoxib withdrawal) or non-continuous (eight or less prescriptions dispensed in the 12 months prior to rofecoxib withdrawal) users. Incidence rate per 100,000 person days and incidence risk ratio described uptake of alternate medicines, following rofecoxib withdrawal. Kaplan-Meier curves described differences in uptake patterns by medicine and pattern of rofecoxib use. Patterns of use of COX-2s in the next 100 days after first COX-2 uptake were described.

Results

Medicine switches and pattern of medicines uptake differed significantly depending upon whether a woman was a continuous or non-continuous rofecoxib user prior to rofecoxib discrediting. Continuous rofecoxib users overwhelmingly switched to another COX-2 and remained continuing COX-2 users for at least 100 days post-switch.

Conclusions

The typical switching behaviour of this group of women suggests that the issues leading to the discrediting of rofecoxib were not seen as a COX-2 class effect by prescribers to this high use group of consumers.

Infrared (810 nm) low-level laser therapy in rat achilles tendinitis: a consistent alternative to drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used and can reduce musculoskeletal pain in spite of the cost of adverse reactions like gastrointestinal ulcers or cardiovascular events. The current study investigates if a safer treatment such as low-level laser therapy (LLLT) could reduce tendinitis inflammation, and whether a possible pathway could be through inhibition of either of the two-cyclooxygenase (COX) isoforms in inflammation. Wistar rats (six animals per group) were injected with saline (control) or collagenase in their Achilles tendons. Then, we treated them with three different doses of IR LLLT (810 nm; 100 mW; 10 s, 30 s and 60 s; 3.57 W cm(-2); 1 J, 3 J, 6 J) at the sites of the injections, or intramuscular diclofenac, a nonselective COX inhibitor/NSAID. We found that LLLT dose of 3 J significantly reduced inflammation through less COX-2-derived gene expression and PGE(2) production, and less edema formation compared to nonirradiated controls. Diclofenac controls exhibited significantly lower PGE(2) cytokine levels at 6 h than collagenase control, but COX isoform 1-derived gene expression and cytokine PGE(2) levels were not affected by treatments. As LLLT seems to act on inflammation through a selective inhibition of the COX-2 isoform in collagenase-induced tendinitis, LLLT may have potential to become a new and safer nondrug alternative to coxibs.

Incidence of spontaneous notifications of adverse reactions with aceclofenac, meloxicam, and rofecoxib during the first year after marketing in the United Kingdom

The objective was to compare the incidence of adverse reactions reported with three nonsteroidal anti-inflammatory drugs with different cyclo-oxygenase (COX)-2 selectivity. All spontaneous adverse reaction notifications in the pharmacovigilance database of the World Health Organisation Collaborating Centre for International Drug Monitoring with aceclofenac, meloxicam, and rofecoxib that were recorded during the first year of marketing were included. The incidence rate (adverse reactions/10⁶ defined daily dose) and 95% confidence interval for total adverse reactions was 8.7 (6.1–12.0) for aceclofenac, 24.8 (23.1–26.6) for meloxicam, and 52.6 (49.9–55.4) for rofecoxib. Aceclofenac had a lower incidence of gastrointestinal bleeding, abdominal pain, and arterial hypertension than meloxicam and a lower incidence of gastrointestinal bleeding, abdominal pain, liver toxicity, thromboembolic cardiovascular events, arterial hypertension, and edema than rofecoxib. The incidence of total and gastrointestinal adverse reactions was significantly lower with aceclofenac than with meloxicam or rofecoxib, thus raising doubts about the hypothetical advantage of COX-2 selective inhibitors.

Selective prescribing of simvastatin and atorvastatin by patient characteristics at treatment initiation over a 7-year period in Finland

PURPOSE

The aim of the study was to investigate preferential initiation with the two most frequently used statins, simvastatin and atorvastatin, by patient characteristics over time.

METHODS

Statin initiators without a statin prescription during the 365 days preceding the initiation from 1 January 1998 through 31 December 2004 were captured from the nation-wide Prescription Register in Finland. Associations of demographic factors and morbidities with atorvastatin versus simvastatin at initiation of statin treatment were analysed by a logistic regression model adjusted for significant covariates separately for each year.

RESULTS

Of all new statin users in 1998, atorvastatin was chosen for 18% and simvastatin for 39%. In 2004, the corresponding figures were 32 and 38%. Atorvastatin was more likely than simvastatin to be initiated in younger age groups than in persons older than 74 years (reference group). Initiation with atorvastatin was less likely for people with than without coronary artery disease; adjusted odds ratios ranged from 0.62 to 0.73 over the years 1998-2003.

CONCLUSION

Channelling of atorvastatin over simvastatin toward the younger and healthier population was found during the first 4 years after its launch in Finland. Channelling may lead to confounding by indication, which must be taken into account when designing pharmacoepidemiology studies on statins.

Prescriber adoption of newly approved selective COX-2 inhibitors

INTRODUCTION

There is no consistent definition of prescribers who adopt new drug treatments early. This study examines if COX-2 inhibitors (coxibs) were prescribed by subsets of practitioners and describes GP adoption patterns of coxibs and existing NSAIDs over time.

METHODS

A population-based drug utilisation study using a Dutch medication claims database. Prescribers of patients (18+yrs) prescribed an NSAID January 1999-December 2003 were identified. Four NSAID categories were chosen reflecting selectivity (coxibs, preferential COX-2 inhibitors and non-selective (ns) NSAIDs (sub-categorised as first or second line treatment)). The characteristics of prescribers issuing>10 prescriptions examined were: Type (GP, Specialist, Other); GP NSAID prescribing preference ratio (nsNSAIDs/coxib first prescription); coxib (ratio<3); prescriber proportion responsible for 100%, 80% and 50% of initiations. Odds Ratios (95%CI) were calculated (first-line nsNSAIDs as reference). Plots of prescribing proportions by quarter year were examined.

RESULTS

NSAID cohorts comprised: first-line ns (N=38783); second-line ns (N=1459); COX-2 preferential (N=3107); coxib (N=4202) patients. For all four cohorts, GPs were the most common prescriber type (>67%); the most frequent prescribing preference was for first-line nsNSAIDs; 50% percentile prescribing proportions were low (<9%). GPs were equally as likely to prescribe coxibs as first-line nsNSAIDs [OR 1.0 (0.9, 1.1)]. Plots of 100% prescriber proportion for first-line nsNSAIDs and coxibs showed convergence; 50th percentile prescriber proportions plots were constant.

CONCLUSIONS

Small subsets of prescribers accounted for the majority of initiations regardless of NSAID type. Further studies are needed on such prescribers to inform healthcare policies and encourage participation in post-marketing safety studies.

Coxibs: evolution of prescription's behaviour in France

The aim of the present study was, first to characterize profiles of coxibs' prescribers [general practitioners (GPs) and rheumatologists] in 2002 in France and, secondly, to identify factors associated with modification of this profile 1 year later. All GPs and rheumatologists from Midi-Pyrenees, Aquitaine, Languedoc-Roussillon and Pays de Loire areas (South of France: 11 050 000 inhabitants) were included in the study. For each practitioner, we used data concerning all non-steroidal anti-inflammatory drugs (NSAIDs) including coxibs reimbursed during period 1 (P1; January-March 2002) and period 2 (P2; January-March 2003). The ratio between the number of coxibs' prescriptions and the total number of NSAIDs' prescriptions (including coxibs) was used to define the two profiles of prescribers, one with a low level of coxibs' prescriptions and another one with a high level of coxibs' prescriptions. Characteristics of practitioners and characteristics of their practices were compared according to this profile. In the second step, we investigated the characteristics (of practitioners and practices) associated with an increase in the level of coxibs' prescriptions in P2 for practitioners with a low level of coxibs' prescriptions in P1. Results are expressed as odds ratio with their 95% confidence intervals. A positive statistical link was found between a high level of coxibs' prescriptions, the speciality of rheumatologist or extra costs for consultation. In contrast, a negative association was observed with female gender or age below 44 years. No relationship was found with the status of referent. Concerning practices' characteristics of practitioners, there was a positive statistical link between a high ratio of coxibs' prescriptions and high co-prescriptions of gastroprotective agents and a negative association with a high number of acts, a high proportion of patients with chronic disabling diseases (CDD) or a high number of patients between 15 and 64 years. There was no statistical link with proportion of patients covered by Universal Medical Coverage (UMC) or aged more than 65 years. Among the factors involved in the increase in the ratio (between P1 and P2), no relationship was found with practitioners' characteristics. In contrast, some factors related to practices (level of gastroprotective co-prescriptions, number of acts, number of CDD patients) were related to a change in coxibs' prescriptions between P1 and P2. This study allowed to discuss some relationships between coxibs' prescription and practitioners' (age, gender, medical speciality or extra costs for consultation) or practices' (level of medical practice, patients' age, number of CDD patients or level of gastroprotective prescriptions) characteristics. In contrast, some other factors like the referent status or the number of patients with UMC are not related. Physicians, initially low prescribers of coxibs and increasing their coxibs' prescriptions during the period of our study, were those with a high level of gastroprotective prescriptions, a low number of acts or a small proportion of CDD patients.

Association of selective and conventional nonsteroidal antiinflammatory drugs with acute renal failure: A population-based, nested case-control analysis

Conventional nonsteroidal antiinflammatory drugs (NSAIDs) are associated with acute renal failure, but cyclooxygenase-2 inhibitors have not been comparatively evaluated. The authors conducted a nested case-control study to assess the association between exposure to NSAIDs, including cyclooxygenase-2 inhibitors, and hospitalization for acute renal failure. They identified 121,722 new NSAID users older than age 65 years from the administrative health care databases of Quebec, Canada, in 1999-2002. Data for 4,228 cases and 84,540 controls matched on age and follow-up time were analyzed by using conditional logistic regression, adjusted for sex, age, health status, health care utilization measures, exposure to contrast agents, and nephrotoxic medications. The risk of acute renal failure for all NSAIDs combined was highest within 30 days of treatment initiation (adjusted rate ratio (RR) = 2.05, 95% confidence interval (CI): 1.61, 2.60) and receded thereafter. The association with acute renal failure within 30 days of therapy initiation was comparable for rofecoxib (RR = 2.31, 95% CI: 1.73, 3.08), naproxen (RR = 2.42, 95% CI: 1.52, 3.85), and nonselective, non-naproxen NSAIDs (RR = 2.30, 95% CI: 1.60, 3.32) but was borderline lower for celecoxib (RR =1.54, 95% CI: 1.14, 2.09; test for interaction comparing celecoxib with rofecoxib, p = 0.057). There was a significant association for both selective and nonselective NSAIDs with acute renal failure, but confirmatory studies are required.

Predictors of the selection of coxibs over nonselective NSAIDs in an older medicaid cohort

BACKGROUND

Cyclooxygenase-2-selective inhibitors (coxibs) have been widely adopted, despite study findings suggesting that they are cost-effective only in certain populations.

OBJECTIVE

This study was conducted to identify factors that were associated with the selection of coxibs rather than nonselective NSAIDs in the period before the emergence of safety concerns in 2004.

METHODS

This was a retrospective cohort analysis of a 15% random sample of Kansas Medicaid beneficiaries aged >60 years that used inpatient, outpatient, and prescription claims data. Subjects were included if they received a prescription for a coxib or nonselective NSAID after a 6-month period without an anti-inflammatory prescription claim and if they underwent at least 90 days of follow-up after the initial prescription. Using 2 previously published models (Dominick et al and Shaya and Blume), we analyzed the impact of factors potentially associated with the preferential selection of a coxib, including age, sex, race, history of upper gastrointestinal disease, chronic or acute use, and recent anticoagulant or corticosteroid therapy.

RESULTS

Study subjects (N = 853) were predominantly female (78.8%) and white (80.4%), and had a mean age of 78 years; 65.1% were prescribed a coxib and 34.9% were prescribed a nonselective NSAID. In bivariate analyses, coxib users were more likely than nonselective NSAID users to be white (83.2% vs 75.3%, respectively; P < 0.05), to be prescribed chronic rather than acute therapy (81.8% vs 58.7%; P < 0.001), and to have a concomitant prescription for warfarin (11.2% vs 5.7%; P < 0.05). Multivariate analyses indicated significance for the same predictors of coxib use: chronic versus acute therapy (Dominick model: adjusted odds ratio [AOR] = 3.39; 95% CI, 2.43-4.74; Shaya model: AOR = 3.39; 95% CI, 2.43-4.74); concomitant anticoagulant therapy (Dominick model: AOR = 2.16; 95% CI, 1.18-3.97; Shaya model: AOR = 2.31; 95% CI, 0.28-0.83); and black race (Dominick model: AOR = 0.48; 95% CI, 0.28-0.83; Shaya model: AOR = 0.49; 95% CI, 0.28-0.84). The most commonly prescribed nonselective NSAIDs were ibuprofen (14.3% of all subjects) and naproxen (6.6% of all subjects); the most commonly prescribed coxibs were rofecoxib (36.5%) and celecoxib (28.5%).

CONCLUSIONS

In this study in an older population, coxibs constituted almost two thirds of all initial anti-inflammatory prescriptions. The prescription of a coxib was influenced by concomitant anticoagulant use and chronic use. Blacks were significantly more likely than whites to receive a nonselective NSAID. Although coxib use has been affected by the association with cardiovascular risk that emerged after the period of this study, rational drug selection and reduction of racial/ethnic disparities remain important targets for improved quality of care.

Use of First- and Second-Generation Cyclooxygenase-2–Selective Nonsteroidal Antiinflammatory Drugs and Risk of Acute Myocardial Infarction

BACKGROUND

The cardiovascular safety of cyclooxygenase (COX)-2-selective nonsteroidal antiinflammatory drugs (NSAIDs) has come under scrutiny after the withdrawal of rofecoxib and halting of the Adenoma Prevention with Celecoxib trial. Whether the newer second-generation COX-2 inhibitors (etoricoxib, valdecoxib) also increase the cardiovascular risk is unknown.

METHODS AND RESULTS

We performed a nested case-control study in a cohort of 486,378 persons registered within the United Kingdom General Practice Research Database with at least 1 prescription of an NSAID between June 1, 2000, and October 31, 2004. A total of 3643 cases with acute myocardial infarction (AMI) were matched to 13,918 controls on age, sex, year of cohort entry, and general practice. Rate ratios (RRs) of AMI associated with use of COX-2-selective and -nonselective NSAIDs were calculated. Current use of etoricoxib was associated with a 2.09-fold (95% confidence interval [CI], 1.10 to 3.97) risk of AMI compared with no use of NSAIDs during the prior year. Current use of rofecoxib (RR=1.29; 95% CI, 1.02 to 1.63), celecoxib (RR=1.56; 95% CI, 1.22 to 2.00), and diclofenac (RR=1.37; 95% CI, 1.17 to 1.59) also significantly increased the AMI risk. For current use of valdecoxib, the RR was 4.60 (95% CI, 0.61 to 34.51). RRs appeared to increase with higher daily doses of COX-2 inhibitors and were also increased in patients without major cardiovascular risk factors.

CONCLUSIONS

Our study supports the hypothesis that the elevated risk of AMI is a class effect of COX-2 inhibitors. The increase in risk appears to be dose dependent, but further data are needed to verify this observation.