Cyclooxygenase-2 inhibitors and coronary occlusion--exploring dose-response relationships

Cardiovascular Risk in Rheumatoid Arthritis: Literature Review

Rheumatoid arthritis (RA) is the most common inflammatory arthritis disease with a worldwide prevalence of 1-3%. RA patients are at higher risk of atherosclerosis than their matched age-sex controls. Cardiovascular diseases (CVDs) account for a 50% risk of increased mortality and morbidity in RA. The pattern of CVD in RA patients differs from that in the general population; RA patients are more likely to have silent ischemic heart disease, sudden death, heart failure, and die early. RA patients tend to have a 5-10 years reduction in their life span than their matched healthy population. Traditional (classical) CV risk factors work separately or synergistically with the underlying inflammation to increase CVD risk in RA. Moreover, inflammation is defined as an independent CVD risk factor. This literature review aims to discuss the traditional CVD risk factors and their association with inflammation in RA.

Nonselective Nonsteroidal Antiinflammatory Drugs and Cardiovascular Risk: Are They Safe?

Objective:

To assess possible cardiovascular risks associated with use of nonselective nonsteroidal antiinflammatory drugs (NSAIDs).

Data Sources:

Medline and Embase were searched from January 1985 through April 2007 and relevant studies were retrieved.

Study Selection and Data Extraction:

Peer-reviewed, prospective, double-blind, case–control, and cohort-design studies published in the English language literature were considered eligible for review. Previous meta-analyses and systematic reviews were also analyzed. In total, 17 case–control studies; 9 cohort studies; 1 prospective, double-blind study; 3 meta-analyses; and 1 systematic review of observational studies were identified.

Data Synthesis:

Three studies were prospective and the remainder consisted of observational, retrospective studies, with most reporting acute fatal or nonfatal myocardial infarction as the cardiovascular endpoint. Among the nonselective NSAIDs, diclofenac appears to pose the highest risk for cardiovascular toxicity; other agents trend toward a neutral effect with respect to cardiovascular risk. Although the data are suggestive, it remains unclear whether naproxen provides protective cardiovascular effects among patients on chronic therapy.

Conclusions:

Currently available data are insufficient for defining evidence-based clinical guidelines for the use of NSAIDs, and the need for additional research, specifically randomized controlled trials, is evident. Diclofenac demonstrates a significant risk while naproxen appears to pose the lowest, albeit nonsignificant, risk for cardiovascular morbidity. Although the current clinical evidence may not warrant recommending naproxen as the preferred NSAID treatment, it may be prudent to avoid diclofenac for patients with cardiovascular risk factors requiring NSAID treatment.

Risk of Bias in Systematic Reviews of Non-Randomized Studies of Adverse Cardiovascular Effects of Thiazolidinediones and Cyclooxygenase-2 Inhibitors: Application of a New Cochrane Risk of Bias Tool

BACKGROUND

Systematic reviews of the effects of healthcare interventions frequently include non-randomized studies. These are subject to confounding and a range of other biases that are seldom considered in detail when synthesizing and interpreting the results. Our aims were to assess the reliability and usability of a new Cochrane risk of bias (RoB) tool for non-randomized studies of interventions and to determine whether restricting analysis to studies with low or moderate RoB made a material difference to the results of the reviews.

METHODS AND FINDINGS

We selected two systematic reviews of population-based, controlled non-randomized studies of the relationship between the use of thiazolidinediones (TZDs) and cyclooxygenase-2 (COX-2) inhibitors and major cardiovascular events. Two epidemiologists applied the Cochrane RoB tool and made assessments across the seven specified domains of bias for each of 37 component studies. Inter-rater agreement was measured using the weighted Kappa statistic. We grouped studies according to overall RoB and performed statistical pooling for (a) all studies and (b) only studies with low or moderate RoB. Kappa scores across the seven bias domains ranged from 0.50 to 1.0. In the COX-2 inhibitor review, two studies had low overall RoB, 14 had moderate RoB, and five had serious RoB. In the TZD review, six studies had low RoB, four had moderate RoB, four had serious RoB, and two had critical RoB. The pooled odds ratios for myocardial infarction, heart failure, and death for rosiglitazone versus pioglitazone remained significantly elevated when analyses were confined to studies with low or moderate RoB. However, the estimate for myocardial infarction declined from 1.14 (95% CI 1.07-1.24) to 1.06 (95% CI 0.99-1.13) when analysis was confined to studies with low RoB. Estimates of pooled relative risks of cardiovascular events with COX-2 inhibitors compared with no nonsteroidal anti-inflammatory drug changed little when analyses were confined to studies with low or moderate RoB. The exception was a rise in the relative risk associated with ibuprofen from 1.07 (95% CI 0.97-1.18) to 1.14 (95% CI 1.03-1.26). The main limitation of our study was testing the instrument on a narrow range of pharmacoepidemiological studies; we cannot assume our findings extend to a broader range of interventions and settings.

CONCLUSIONS

The Cochrane RoB tool highlighted a wide range of risks of bias in studies included in two widely cited reviews and had the potential to change the conclusions of the reviews. Systematic reviews that incorporate non-randomized studies of medical interventions should include a detailed assessment of RoB for each included study.

Myocardial infarction and individual nonsteroidal anti-inflammatory drugs meta-analysis of observational studies

Objective

To conduct a systematic review of observational studies on the risk of acute myocardial infarction (AMI) with use of individual nonsteroidal anti-inflammatory drugs (NSAIDs).

Methods

A search of Medline (PubMed) for observational studies published from 1990 to 2011 identified 3829 articles; 31 reported relative risk (RR) of AMI with use of individual NSAIDs versus nonuse of NSAIDs. Information abstracted in a standardized form from 25 publications was used for the meta-analysis on 18 independent study populations.

Results

Random-effects RR (95% confidence interval (CI)) was lowest for naproxen 1.06 (0.94–1.20), followed by celecoxib 1.12 (1.00–1.24), ibuprofen 1.14 (0.98–1.31), meloxicam 1.25 (1.04–1.49), rofecoxib 1.34 (1.22–1.48), diclofenac 1.38 (1.26–1.52), indometacin 1.40 (1.21–1.62), etodolac 1.55 (1.16–2.06), and etoricoxib 1.97 (1.35–2.89). Heterogeneity between studies was present. For new users, RRs (95% CIs) were for naproxen, 0.85 (0.73–1.00); ibuprofen, 1.20 (0.97–1.48); celecoxib, 1.23 (1.00–1.52); diclofenac, 1.41 (1.08–1.86); and rofecoxib, 1.43 (1.21–1.66).

Except for naproxen, higher risk was generally associated with higher doses, as defined in each study, overall and in patients with prior coronary heart disease. Low and high doses of diclofenac and rofecoxib were associated with high risk of AMI, with dose–response relationship for rofecoxib. In patients with prior coronary heart disease, except for naproxen, duration of use ≤3 months was associated with an increased risk of AMI.

Conclusions

Most frequently NSAIDs used in clinical practice, except naproxen, are associated with an increased risk of AMI at high doses or in persons with diagnosed coronary heart disease. For diclofenac and rofecoxib, the risk was increased at low and high doses. Copyright © 2013 John Wiley & Sons, Ltd.

NSAID use and association with cardiovascular outcomes in outpatients with stable atherothrombotic disease

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) other than aspirin have been linked to heart failure, salt retention, adverse ventricular remodeling, and thrombosis. We therefore sought to assess their impact on cardiovascular events in outpatients with stable atherothrombotic disease.

METHODS

We analyzed 44,095 patients in the REduction of Atherothrombosis for Continued Health (REACH) registry with information on NSAID use and 4-year follow-up. Cox proportional hazard models, including NSAID use as a time-dependent covariate, were constructed and adjusted for key baseline characteristics. End points of interest included multivariate adjusted: cardiovascular death/myocardial infarction/stroke/ischemic hospitalizations; cardiovascular death/myocardial infarction/stroke; hospitalization for heart failure; and individual components of the composite end points.

RESULTS

Compared with NSAID nonusers (n = 39,675), NSAID users (n = 4420) were older (70 vs 68 years), more frequently female and white, and had more baseline heart failure and atherosclerotic risk factors (hypertension, dyslipidemia, diabetes, reduced creatinine clearance) (all P < .001). NSAID use was associated with an increased hazard for cardiovascular death/myocardial infarction/stroke/ischemic hospitalizations (adjusted hazard ratio [adj. HR] 1.12; 95% confidence interval [CI], 1.04-1.21; P = .003) and for cardiovascular death/myocardial infarction/stroke (adj. HR 1.16; 95% CI, 1.03-1.30; P = .02). There also was a higher risk of myocardial infarction (adj. HR 1.37; 95% CI, 1.12-1.68; P = .002), stroke (adj. HR 1.21; 95% CI, 1.00-1.45; P = .048), heart failure hospitalizations (adj. HR 1.18; 95% CI, 1.03-1.34; P = .013), and ischemic hospitalizations (adj. HR 1.17; 95% CI, 1.07-1.27; P = .001).

CONCLUSION

Among patients with stable atherothrombosis, NSAID use is associated with a higher risk of myocardial infarction, stroke, and hospitalizations for both ischemia and heart failure.

Coxibs: pharmacology, toxicity and efficacy in cancer clinical trials

This chapter briefly summarizes the current knowledge about the role of nonsteroidal anti-inflammatory drugs (NSAIDs), specially focusing on those selective for cyclooxygenase (COX)-2 (coxibs), on colorectal cancer (CRC) onset, and progression. Both epidemiological and experimental studies have reported that these drugs reduce the risk of developing colonic tumors. However, the promising use of coxibs in chemoprevention was halted abruptly due to the detection on enhanced cardiovascular (CV) risks. Thus, we discuss the clinical data and plausible mechanisms of CV hazards associated with traditional NSAIDs and coxibs. The extent of inhibition of COX-2-dependent prostacyclin, an important vasoprotective and anti-thrombotic pathway, in the absence of a complete suppression of COX-1-dependent platelet function, at common doses of NSAIDs, might play a role in CV toxicity. Coxibs might still be reserved for younger patients with familial adenomatous polyposis (FAP). However, it should be taken into consideration that recent findings of enhanced thromboxane (TX)A(2) biosynthesis in colon tumorigenesis, detected in humans. In this context, the use of low-dose aspirin (which mainly acts by inhibiting platelet COX-1-dependent TXA(2)) may have a place for chemoprevention of CRCs (see also Chap. 3 ). The possible use of coxibs to prevent CRC will depend mainly on research progresses in biomarkers able to identify the patients uniquely susceptible to developing thrombotic events by inhibition of COX-2.

Cardiovascular safety of celecoxib in acute myocardial infarction patients: a nested case-control study

The objective was to measure the impact of exposure to coxibs and non-steroidal antiinflammatory drugs (NSAID) on morbidity and mortality in older patients with acute myocardial infarction (AMI). A nested case-control study was carried out using an exhaustive population-based cohort of patients aged 66 years and older living in Quebec (Canada) who survived a hospitalization for AMI (ICD-9 410) between 1999 and 2002. The main variables were all-cause and cardiovascular (CV) death, subsequent hospital admission for AMI, and a composite end-point including recurrent AMI or CV death. Conditional logistic regressions were used to estimate the risk of mortality and morbidity. A total of 19,823 patients aged 66 years and older survived hospitalization for AMI in the province of Quebec between 1999 and 2002. After controlling for covariables, the risk of subsequent AMI and the risk of composite end-point were increased by the use of rofecoxib. The risk of subsequent AMI was particularly high for new rofecoxib users (HR 2.47, 95% CI 1.57–3.89). No increased risk was observed for celecoxib users. No increased risk of CV death was observed for patients exposed to coxibs or NSAIDs. Patients newly exposed to NSAIDs were at an increased risk of death (HR 2.22, 95% CI 1.30–3.77) and of composite end-point (HR 2.28, 95% CI 1.35–3.84). Users of rofecoxib and NSAIDs, but not celecoxib, were at an increased risk of recurrent AMI and of composite end-point. Surprisingly, no increased risk of CV death was observed. Further studies are needed to better understand these apparently contradictory results.

All-cause mortality of elderly Australian veterans using COX-2 selective or non-selective NSAIDs: a longitudinal study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Previous studies have found varying impact of exposure to COX-2 selective and non-selective NSAIDs.

WHAT THIS STUDY ADDS

• Individuals receiving a COX-2 selective NSAID had an increased risk of all-cause mortality after correction for age, sex and cardiovascular risk as measured by co-prescription. • Despite differences in the pharmacokinetic properties of the COX-2 selective inhibitor drugs, our study lends no support to clinicians preferring any one COX-2 selective inhibitor drug, or substituting one for another on the grounds of mortality risk alone. • The Australian Department of Veterans' Affairs data sets make it possible to conduct timely record linkage studies of all-cause mortality from use of medicines in a large and clinically relevant population.

AIM

To determine hazard ratios for all-cause mortality in elderly Australian veterans taking COX-2 selective and non-selective NSAIDs.

METHODS

Patient cohorts were constructed from claims databases (1997 to 2007) for veterans and dependants with full treatment entitlement irrespective of military service. Patients were grouped by initial exposure: celecoxib, rofecoxib, meloxicam, diclofenac, non-selective NSAID. A reference group was constructed of patients receiving glaucoma/hypothyroid medications and none of the study medications. Univariate and multivariate analyses were performed using Cox proportional hazards regression models. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated for each exposure group against each of the reference group. The final model was adjusted for age, gender and co-prescription as a surrogate for cardiovascular risk. Patients were censored if the gap in supply of study prescription exceeded 30 days or if another study medication was initiated. The outcome measure in all analyses was death.

RESULTS

Hazard ratios and 95% CIs, adjusted for age, gender and cardiovascular risk, for each group relative to the reference group were: celecoxib 1.39 (1.25, 1.55), diclofenac 1.44 (1.28, 1.62), meloxicam 1.49 (1.25, 1.78), rofecoxib 1.58 (1.39, 1.79), non-selective NSAIDs 1.76 (1.59, 1.94).

CONCLUSIONS

In this large cohort of Australian veterans exposed to COX-2 selective and non-selective NSAIDs, there was a significant increased mortality risk for those exposed to either COX-2-selective or non-selective NSAIDs relative to those exposed to unrelated (glaucoma/hypothyroid) medications.

Selective COX-2 inhibitors, NSAIDs and congestive heart failure: differences between new and recurrent cases

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Pharmaco-epidemiological studies have shown that in susceptible individuals, nonsteroidal anti-inflammatory drugs (NSAIDs) and selective cyclooxygenase (COX)-2 inhibitors increase the risk of developing congestive heart failure (CHF). Recently published studies have found lower relative risk (RR) estimates than the initial studies published in 1998-2000. It is unclear whether the level of risk is elevated equally in first time and recurrent cases of CHF.

WHAT THIS STUDY ADDS

This study found low-level, statistically nonsignificant elevations of risk with NSAIDs and COX-2 inhibitors. There was a much higher level of recent use of NSAIDs/COX-2 inhibitors among first-time cases than among recurrent cases of CHF. * The dilution of the RR over successive studies, and the differences between first-time and recurrent cases noted here, suggest that prescribing doctors have heeded advice about the cardiovascular risks of NSAIDs and extended this practice to selective COX-2 inhibitors.

AIMS

To quantify the association between treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) and selective cyclooxygenase (COX)-2 inhibitors and hospitalization due to congestive heart failure (CHF); to determine if the risk varies between first and subsequent episodes of CHF.

METHODS

We conducted a case-control study of the relationship between recent use of NSAIDs and COX-2 inhibitors and hospitalization with CHF. Cases (n = 530) were patients admitted to hospital with a primary diagnosis of CHF. Controls (n = 1054) were subjects without CHF who were admitted to the same hospitals as the cases. They were frequency matched to cases on the basis of age and sex. Structured interviews were used to obtain information on a number of study factors, including recent use of NSAIDs and COX-2 inhibitors. Relative risks (RRs) were estimated from exposure odds ratios, adjusted for a range of potential confounders.

RESULTS

Overall, NSAIDs and COX-2 inhibitors had been taken by 249 (23.6%) controls in the week before admission to hospital. Use of any NSAID/COX-2 inhibitor was recorded in 81/285 (28.4%) first-time cases compared with 38/245 (15.5%) in recurrent cases: difference 12.9% (95% confidence interval 5.9, 19.8) (P = 0.0004). The adjusted RRs for first hospital admission for CHF with different drug exposures were: NSAIDs 1.1 (0.67, 1.83), rofecoxib 1.29 (0.78, 2.13) and celecoxib 1.47 (0.85, 2.53).

CONCLUSIONS

We found weak and statistically nonsignificant associations between use of NSAIDs and COX-2 inhibitors and hospitalization with CHF. This low RR is consistent with the results of recently published studies, but not with early studies that found an approximate doubling of risk with use of NSAIDs. The dilution of risk and the significantly lower levels of prescribing for recurrent than for first-time cases of heart failure suggest that prescribing doctors heeded messages that NSAIDs may precipitate CHF in vulnerable individuals, and that they have applied the same message to selective COX-2 inhibitors.

Are COX-2 inhibitors preferable to non-selective non-steroidal anti-inflammatory drugs in patients with risk of cardiovascular events taking low-dose aspirin?

Cyclo-oxygenase-2 selective inhibitors and non-selective non-steroidal anti-inflammatory drugs (NSAIDs) are associated with increased risk of acute cardiovascular events. Only aspirin offers primary and secondary cardiovascular prophylaxis, but trials have not answered directly whether low-dose aspirin is cardioprotective with COX-2 inhibitors. A large inception cohort study showed that concomitant use of aspirin reduced risk of cardiovascular events when given with rofecoxib, celecoxib, sulindac, meloxicam, and indometacin but not when given with ibuprofen. In large trials assessing gastrointestinal safety, there were fewer gastrointestinal events in patients using both COX-2 inhibitors and aspirin than in those using non-selective NSAIDs and aspirin; significantly fewer uncomplicated upper gastrointestinal events took place in the MEDAL trial. Analysis of VIGOR and two capsule endoscopy studies showed significantly less distal gastrointestinal blood loss with COX-2 inhibitors than with non-selective NSAIDs. Endoscopy trials showed that low-dose aspirin does not diminish the gastrointestinal benefits of COX-2 inibitors over non-selective NSAIDs. In an elderly epidemiological cohort receiving aspirin, both celecoxib and rofecoxib reduced risk of admission for gastrointestinal events. Comparison of the cardiovascular and gastrointestinal risks is difficult: likelihood and severity of cardiovascular events differ between individuals, agents, and exposure. Mortality associated with gastrointestinal events is less frequent than with cardiovascular events, but asymptomatic ulcers can result in severe complications. Data support the conclusion that COX-2 inhibitors are preferable to non-selective NSAIDs in patients with chronic pain and cardiovascular risk needing low-dose aspirin, but relative risks and benefits should be assessed individually for each patient.