Current Use of Selective Serotonin Reuptake Inhibitors and Risk of Acute Myocardial Infarction

Estimating the effect of current, previous and never use of drugs in studies based on prescription registries

PURPOSE

Many studies which investigate the effect of drugs categorize the exposure variable into never, current, and previous use of the study drug. When prescription registries are used to make this categorization, the exposure variable possibly gets misclassified since the registries do not carry any information on the time of discontinuation of treatment.In this study, we investigated the amount of misclassification of exposure (never, current, previous use) to hormone therapy (HT) when the exposure variable was based on prescription data. Furthermore, we evaluated the significance of this misclassification for analysing the risk of breast cancer.

MATERIALS AND METHODS

Prescription data were obtained from Danish Registry of Medicinal Products Statistics and we applied various methods to approximate treatment episodes. We analysed the duration of HT episodes to study the ability to identify discontinuation of therapy from prescription data. Furthermore, we compared to results based on self-reported duration of HT from the Danish Nurse Cohort.Finally, we analysed the effect of HT exposure on time to breast cancer for the different prescription based exposure variables as well as for self-reported HT use.

RESULTS

The results of time to discontinuation varied strongly across the different HT assessments. However, misclassification of HT exposure at baseline was limited and hence analysis of the effect of HT on time to breast cancer showed stability across the different exposure assessments with Hazard Ratios ranging from 1.68 to 1.78 for current use compared to never use.

CONCLUSIONS

The findings suggest that it is possible to estimate the effect of never, current and previous use of HT on breast cancer using prescription data.

Antidepressant use, depression, and survival in patients with heart failure

BACKGROUND

Recent studies suggest that the use of antidepressants may be associated with increased mortality in patients with cardiac disease. Because depression has also been shown to be associated with increased mortality in these patients, it remains unclear if this association is attributable to the use of antidepressants or to depression.

METHODS

To evaluate the association of long-term mortality with antidepressant use and depression, we studied 1006 patients aged 18 years or older with clinical heart failure and an ejection fraction of 35% or less (62% with ischemic disease) between March 1997 and June 2003. The patients were followed up for vital status annually thereafter. Depression status, which was assessed by the Beck Depression Inventory (BDI) scale and use of antidepressants, was prospectively collected. The main outcome of interest was long-term mortality.

RESULTS

Of the study patients, 30.0% were depressed (defined by a BDI score > or =10) and 24.2% were taking antidepressants (79.6% of these patients were taking selective serotonin reuptake inhibitors [SSRIs] only). The vital status was obtained from all participants at an average follow-up of 972 (731) (mean [SD]) days. During this period, 42.7% of the participants died. Overall, the use of antidepressants (unadjusted hazard ratio [HR], 1.32; 95% confidence interval [CI], 1.03-1.69) or SSRIs only (unadjusted HR, 1.32; 95% CI, 0.99-1.74) was associated with increased mortality. However, the association between antidepressant use (HR, 1.24; 95% CI, 0.94-1.64) and increased mortality no longer existed after depression and other confounders were controlled for. Nonetheless, depression remained associated with increased mortality (HR, 1.33; 95% CI, 1.07-1.66). Similarly, depression (HR, 1.34; 95% CI, 1.08-1.68) rather than SSRI use (HR, 1.10; 95% CI, 0.81-1.50) was independently associated with increased mortality after adjustment.

CONCLUSION

Our findings suggest that depression (defined by a BDI score > or =10), but not antidepressant use, is associated with increased mortality in patients with heart failure.

Effect of selective serotonin reuptake inhibitors on cardiovascular morbidity and mortality

Depression in patients with coronary artery disease is associated with increased cardiovascular morbidity and mortality. It is not clear, however, if treatment with selective serotonin reuptake inhibitors (SSRIs) decreases the rate of future cardiovascular events. This paper reviews the available literature regarding the effect of SSRI use on cardiovascular outcomes. Thirteen studies addressing this issue were identified. Of these, 5 concluded that SSRI use is associated with decreased cardiovascular morbidity or mortality, 2 concluded that SSRI use was associated with worsened prognosis, and 6 studies found no statistically significant association. Almost all of the published literature examining the effect of SSRIs on cardiovascular outcomes is based on observational studies, thereby precluding definitive conclusions. Randomized controlled studies are clearly needed to definitively address this issue.

Moderate and high affinity serotonin reuptake inhibitors increase the risk of upper gastrointestinal toxicity

OBJECTIVE

Serotonin release from platelets is important for regulating hemostasis. Some prior studies suggest an association between use of selective serotonin reuptake inhibitors and gastrointestinal bleeding and a possible synergistic effect of these medications with non-steroidal anti-inflammatory drugs (NSAIDs). This study examined the effect of medications that inhibit serotonin uptake on upper gastrointestinal toxicity.

METHODS

359 case subjects hospitalized for upper gastrointestinal bleeding, perforation, or benign gastric outlet obstruction were recruited from 28 hospitals. 1889 control subjects were recruited by random digit dialing from the same region. Data were collected during structured telephone interviews. Antidepressant medications were characterized according to their affinity for serotonin receptors. Exposure to medications required use on at least 1 day during the week prior to the index date.

RESULTS

Any moderate or high affinity serotonin reuptake inhibitor (MHA-SRI) use was reported by 61 cases (17.1%) and 197 controls (10.4%). After adjusting for potential confounders, MHA-SRI use was associated with a significantly increased odds of hospitalization for upper gastrointestinal toxicity (adjusted OR = 2.0, 95%CI 1.4-3.0). A dose-response relationship in terms of affinity for serotonin uptake receptors was not observed (p = 0.17). No statistical interaction was observed for use of high dose NSAIDs or aspirin concomitantly with MHA-SRIs (p = 0.5). When MHA-SRIs were used concomitantly with high dose NSAIDs, the adjusted odds ratio for the association with upper gastrointestinal toxicity was 3.5 (95%CI 1.9-6.6).

CONCLUSIONS

Use of MHA-SRIs is associated with an increased risk of hospitalization for upper gastrointestinal toxicity.

A secondary analysis of a duration response association between selective serotonin reuptake inhibitor use and the risk of acute myocardial infarction in the aging population

PURPOSE

We assessed the risk of selective serotonin reuptake inhibitor (SSRI) use on the occurrence of acute myocardial infarction (AMI) based on duration of exposure.

METHODS

A historical pooled cohort of all elderly, community-dwelling Medicare beneficiaries not enrolled in health maintenance organizations from the 1997 to 2001 Medicare Current Beneficiary Survey was constructed. SSRI users were compared with non-antidepressant users as well as other non-SSRI antidepressant users on their risk of AMI (ICD-9: 410 or 411). Descriptive statistics and binary logistic regression models were used to assess differences between groups.

RESULTS

There were 1,052 SSRI users compared with 762 other antidepressant users and 10,856 nonantidepressant users. Logistic regression models revealed that SSRI users were found to have significantly greater odds of AMI compared with nonantidepressant users when controlling for age, gender, race, smoking history and current status, body mass index, depression, anxiety and diabetes (odds ratio 1.85; 95% confidence intervals 1.13-3.04). Stratification by prescription counts revealed those with more than three prescriptions had greater odds of AMI compared with nonusers (odds ratio 2.02, 95% confidence intervals 1.11-3.66).

CONCLUSIONS

SSRI use leads to an increased risk of AMI in comparison with nonantidepressant use in an elderly population. The odds of AMI increased in those with more than three prescriptions in the preceding year, indicating a possible duration response relationship.

Channelling of SSRIs and SNRIs use in the Tayside population, Scotland

PURPOSE

To compare the user profiles of the two classes of drug, using the Tayside Medicines Monitoring Unit (MEMO) record-linkage database.

METHODS

A cohort study was carried out in the population of Tayside in Scotland. A total of 13 901 selective serotonin re-uptake inhibitor (SSRI) users and 1417 selective norepinephrine re-uptake inhibitor (SNRI) users were identified during the period of December 2000 to November 2001. A logistic regression model was used to assess the association between drug use and patients profiles and a Cox regression model was employed to examine the effect of drug use and mortality outcome.

RESULTS

Compared to SNRI patients, SSRI patients were significantly older (28.8% >/= 60 year vs. 26.2%), more likely to be female (70.9% vs. 67.8%), had more cardiovascular disease history (10.1% vs. 8.5%), but were less deprived (9.7% in the highest deprivation category vs. 12.4%), had less digestive disease (27.9% vs. 31.0%) and less history of drug overdose hospitalisation (7.2% vs. 11.9%). SNRI patients had more drug switching than SSRI patients (62.0% for recent users, 33.2% for prevalent users vs. 39.1%, 26.1%, respectively). The age-standardised mortality rates during the follow-up period until December 2003 were 5.3% for SSRI and 5.9% for SNRI users.

CONCLUSION

There was clear evidence that SSRI and SNRI were used in patient groups with different characteristics. This channelling sometimes favoured an improved mortality outcome and sometimes favoured a worse outcome. Overall there was no mortality difference between the two classes of drugs.

Specific serotonin reuptake inhibition in major depressive disorder adversely affects novel markers of cardiac risk

There exists a growing body of evidence linking depression with cardiovascular events, although the mechanisms responsible remain unknown. We investigated the role of the autonomic nervous system and inflammation in the link between coronary heart disease and major depressive disorder (MDD), and examined the cardiac risk modification following pharmacological treatment of depression. We measured cardiac baroreflex function, heart rate variability, pulse pressure and high sensitivity C-reactive protein (hsCRP), all of which have an impact on cardiac risk, pre- and post-treatment in 25 patients with MDD, with no history of coronary heart disease, and in 15 healthy subjects. Treatment consisted of selective serotonin reuptake inhibitors for approximately 12 weeks. No significant differences were observed between untreated MDD patients and healthy subjects in blood pressure, heart rate, baroreflex sensitivity or heart rate variability. Pulse pressure and hsCRP, however, were significantly elevated in patients with MDD prior to treatment (p=0.023 and p=0.025, respectively). Moreover, while pharmacotherapy was effective in alleviating depression, surprisingly, each of cardiac baroreflex function, heart rate variability, pulse pressure and hsCRP was modified (p<0.05) in a manner likely to increase cardiac risk. In conclusion, this study demonstrated higher pulse pressure and hsCRP plasma levels in patients with MDD, which might contribute to increased cardiac risk. Following treatment vagal activity was reduced, as indicated by reductions in baroreflex sensitivity and heart rate variability, accompanied by increases in pulse pressure and plasma hsCRP levels. Mechanisms potentially responsible for generating cardiac risk in patients treated with selective serotonin reuptake inhibitors may need to be therapeutically targeted to reduce the incidence of coronary heart disease in this population.

Depression and cardiovascular comorbidity

Depression has long had a popular link to cardiovascular disease and death. However, only during the last 15 years has scientific evidence supporting this common wisdom been available. Beginning in the early 1990s, there began to accumulate community-based epidemiological evidence that medically healthy depressed patients followed for long periods of time were at increased risk of both cardiovascular disease and cardiac death. In the mid-1990s, evidence appeared to indicate that depression following a heart attack increased the risk of death. It is now apparent that depression aggravates the course of multiple cardiovascular conditions. There are two major unanswered questions. One is whether treating depression will reduce the risk of cardiovascular disease and death. Here, preliminary, but not definitive, evidence suggests that the serotonin reuptake inhibitors may be useful. The other unanswered question regards the mechanisms that underlie this link between depression and cardiovascular disease. There is strong evidence linking platelet activation, autonomic activity, and inflammatory markers to both depression and heart disease, but why these links exist is far less clear.

Selective serotonin reuptake inhibitor use by patients with acute coronary syndromes

BACKGROUND

Selective serotonin reuptake inhibitors are commonly used to treat anxiety, depression, and other conditions that commonly affect patients with coronary artery disease. Selective serotonin reuptake inhibitors inhibit platelet activation and may, therefore, affect outcomes in patients with acute coronary syndromes.

METHODS

A retrospective study was performed of 1254 patients with acute coronary syndromes comparing in-hospital bleeding and cardiac event rates in 158 patients who received a selective serotonin reuptake inhibitor and a propensity score-matched group of patients who did not. All patients were treated with a glycoprotein IIb/IIIa inhibitor and almost all also received aspirin, clopidogrel, and heparin.

RESULTS

Patients who received a selective serotonin reuptake inhibitor were significantly more likely to experience any bleeding (37.3% vs 26.6%, OR 1.65, 95% confidence interval (CI), 1.02-2.66, P =.04) and significantly less likely to experience recurrent myocardial ischemia, heart failure, or asymptomatic cardiac enzyme elevation while in the hospital (7.0% vs 13.9%, OR 0.46, 95% CI, 0.22-0.99, P =.04). No differences were observed in death, myocardial infarction during the hospitalization, urgent revascularization, or major bleeding. Bleeding and cardiac events were not affected by antidepressants other than selective serotonin reuptake inhibitors.

CONCLUSIONS

Selective serotonin reuptake inhibitor use during a hospitalization for an acute coronary syndrome is associated with reduced rates of recurrent ischemia, heart failure, or cardiac enzyme elevation at the expense of increased bleeding in patients receiving maximal conventional antiplatelet medications and heparin. Clinicians should be aware of this association when treating patients with an acute coronary syndrome.

Prognosis of patients taking selective serotonin reuptake inhibitors before coronary artery bypass grafting

Depression is increasingly recognized as an independent prognostic risk factor in patients with coronary artery disease and coronary artery bypass grafting (CABG). The use of selective serotonin reuptake inhibitors (SSRIs) for depression in patients with cardiac disease is becoming more prevalent. We examined the long-term outcomes of patients on SSRIs before CABG. We prospectively examined collected data in the Duke Databank for Cardiovascular Disease from January 1, 1999 to December 31, 2003. The median and maximum follow-up periods were 3 and 6 years, respectively. We screened patients who underwent CABG (n = 5,364) and excluded those who underwent simultaneous CABG and valvular surgery (n = 570). SSRI antidepressants included fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, escitalopram, venlafaxine, and clomipramine, and their use was determined from the inpatient pharmacy records during the index hospitalization. Outcomes included event-free survival from all-cause mortality, rehospitalization, and a composite end point of all-cause mortality or rehospitalization. Of 4,794 CABG-only patients, 246 (5.1%) took SSRIs before CABG. The SSRI group had a higher prevalence of diabetes, hypercholesterolemia, hypertension, cerebrovascular disease, peripheral vascular disease, and previous cardiovascular intervention. After adjustment for baseline differences, patients on SSRIs before CABG had increased risks of mortality, rehospitalization, and the composite end point (hazard ratio 1.61, 95% confidence interval 1.17 to 2.21, p = 0.003; hazard ratio 1.52, 95% confidence interval 1.30 to 1.77, p <0.0001; and hazard ratio 1.46, 95% confidence interval 1.26 to 1.70, p <0.0001, respectively). In conclusion, SSRI use before CABG was associated with a higher risk of long-term post-CABG mortality and rehospitalization. The explanation behind these findings requires further research.

Treatment of anxiety disorders with venlafaxine XR

When venlafaxine was introduced in 1994, it was the first of the newer generation antidepressants to be classified as a serotonin norepinephrine reuptake inhibitor (SNRI). An extended release (XR) formulation of venlafaxine, introduced in 1997, subsequently received regulatory approval for treatment of three anxiety disorders: generalized anxiety disorder, social anxiety disorder and panic disorder. Although less extensively studied, venlafaxine XR also appears to have efficacy for two other anxiety disorders, post-traumatic stress disorder and obsessive-compulsive disorder. In contrast to the treatment of depression, for which meta-analyses suggest an efficacy advantage relative to selective serotonin reuptake inhibitors (SSRIs), evidence of differential efficacy has not yet been established for any of the anxiety disorders. The overall tolerability profile of venlafaxine XR is generally comparable to that of the SSRIs, although there is greater incidence of noradrenergically mediated side effects (i.e., dry mouth and constipation), as well as a dose-dependent risk of treatment-emergent high blood pressure. Concerns about safety in overdose have also recently emerged. Despite these caveats, venlafaxine XR is an effective and generally well-tolerated option for treatment of anxiety disorders.

Anaesthesia for patients with mood disorders

PURPOSE OF REVIEW

Treatment of patients with mood disorders has changed over the past few years. It is not always clear how the anaesthesiologist has to incorporate these antidepressants and mood stabilizers in premedication or even how to anticipate any interaction with anaesthetic technique.

RECENT FINDINGS

The older generation of antidepressants (tricyclic antidepressants, monoamine oxidase inhibitors) is seldom used nowadays. Actually, treatment with selective serotonin-reuptake inhibitors, serotonin noradrenaline-reuptake inhibitors, noradrenaline-reuptake inhibitor, noradrenergic and specific serotonin antidepressants, or noradrenaline- and dopamine-reuptake inhibitors is common practice. Combination with atypical antipsychotics and newer antiepileptics is suggested as an add-on therapy or as monotherapy, while lithium and valproate therapy is still the first choice in bipolar mood stabilization. Electroconvulsive therapy is still used in therapy-resistant forms of depression; however, the anaesthesia technique herein has been increasingly well described in the last years. Electroencephalogram-derived monitoring such as bispectral index (BIS) can be used as a tool to predict seizure duration. Intoxications with these newer agents are not infrequent and deserve specific attention. In particular, serotonin syndrome is a life-threatening condition that requires great care by the anaesthesiologist. The chronic use of antidepressants does affect the anaesthetized patient: hypotension, arrhythmias, changed thermoregulation, altered postoperative pain, differences in surgical stress response and postoperative confusion. However, it is advised to continue these drugs in the perioperative period.

SUMMARY

Discontinuation of treatment with the new antidepressants in the perioperative period is not advised. Intoxication with the newer drugs appears to be safer. The anaesthesiologist must pay attention to serotonin syndrome. Electroconculsive therapy has gained renewed attention.

Pharmacotherapy of depression in old age

This review addresses the pharmacotherapy of antidepressants in the elderly. We performed a search based on Medline and the Cochrane Library. In addition to a meta-analysis of 17 randomised controlled studies, 36 randomised controlled trials of patients over the age of 60 published between 1980 and 2005 in English met the selection criteria and were included. Existing evidence suggests that no one class of antidepressant drugs has been found to be more effective than another in the treatment of depression in the elderly. Although newer antidepressants are not more effective than older ones, they are better tolerated and are safe especially in overdose. The adverse effect data suggest modest superiority of selective serotonin reuptake inhibitors over tricyclic antidepressants. The evidence available indicates that antidepressant treatment of four weeks has a beneficial effect compared to placebo. As to prevention of relapse and recurrence, antidepressants should be continued for at least six months after good initial response. In patients with high risk of relapse, treatment should be continued for at least two years. Long-term efficacy has been shown for dosulepin, nortriptyline and citalopram. In patients with dementia with persistent and significant symptoms antidepressant treatment may be indicated. At present, clomipramine, citalopram and sertraline have been reported as being superior to placebo. There is a paucity of data on the use of antidepressants in very elderly individuals, patients with significant comorbidity and patients with dementia. More data on the effect of antidepressants in the elderly, especially in the over 80-age group are needed.