Potential limitations of electronic database studies of prescription non-aspirin non-steroidal anti-inflammatory drugs (NANSAIDs) and risk of myocardial infarction (MI)

PURPOSE

To determine whether specific limitations in electronic database studies may lead to biased estimates of the association between prescription, non-selective non-aspirin non-steroidal anti-inflammatory drugs (NANSAIDs) and myocardial infarction (MI) METHODS: Using our case-control study of NANSAIDs and first, non-fatal MI, we determined the odds ratio (OR) for prescription NANSAIDs and MI. In the 'Replicating Electronic Database Analysis,' we considered non-prescription NANSAID users to be 'non-users,' did not stratify by aspirin use, and did not adjust for confounders typically unavailable or incomplete in existing databases. In the 'Misclassification Assessment Analysis,' we removed non-prescription NANSAIDs from the 'non-user' category. In the 'Confounding Assessment Analysis #1,' we additionally adjusted for smoking, family history, and years of education. In the 'Confounding Assessment Analysis #2,' we also adjusted for body mass index (BMI) and physical activity. In the 'Interaction Assessment Analysis,' we stratified on aspirin use and repeated the latter analysis.

RESULTS

The prevalence of current NANSAID and aspirin use was higher in our controls than in electronic database studies, consistent with the fact that non-prescription NANSAIDs accounted for 81% of all NANSAID use. Education, physical activity, and BMI also were associated with prescription NANSAID use. When each potential source of bias was removed, the OR for NANSAIDs moved further from 1.0 (i.e., toward a protective association with MI): 'Replicating Electronic Database' analysis (OR 1.00, 95% confidence interval [CI]: 0.78--1.28); 'Misclassification Assessment Analysis' (OR 0.89, 95%CI: 0.70--1.14); 'Confounding Assessment Analysis #1' (OR 0.85, 95%CI: 0.66--1.10); 'Confounding Assessment Analysis #2' (OR 0.78, 95%CI: 0.60--1.01); 'Interaction Assessment Analysis' (OR 0.69, 95%CI: 0.51--0.95).

CONCLUSIONS

Limitations in electronic databases may be responsible for the lack of association of NANSAIDs on lower MI risk noted in these studies. Further studies-preferably randomized trials-are needed to address the risk-benefit ratio of NANSAID use.

The effect of cardiac troponin testing on clinical care in a veterans population: a randomized controlled trial

BACKGROUND

Cardiac troponin is more accurate than creatine kinase (CK) testing for detecting myocardial injury in patients with acute coronary syndromes (ACS), but its effects on clinical care compared with CK testing alone is open to question.

OBJECTIVE

To test the effects of troponin I on medical decisions for patients undergoing cardiac enzyme testing.

DESIGN

Randomized, controlled trial.

SETTING

Urban academic Veterans Affairs medical center.

PATIENTS

Three hundred ninety-two patients presenting to the emergency department (ED) and outpatient settings with symptoms and/or electrocardiograms suggestive but not diagnostic of ACS.

INTERVENTION

Random assignment to linked CK-troponin I (CKTnI) testing or CK testing alone.

MEASUREMENTS

ED discharge and cardiac catheterization incidence (primary); ED medication use, inpatient noninvasive testing, revascularization procedures, discharge medications, and 8-week ED visits, hospitalizations, and procedures (secondary).

RESULTS

Groups were similar in all variables except history of heart failure (CK 26.8% vs CKTnI 17.0%). ACS comprised 12.2% of the cohort. ED discharge incidence was greater in the CKTnI arm (18% vs 9.6%; relative risk [RR], 1.83; 95% CI, 1.08 to 3.31; P=.02; number needed to test=12.6; 95% CI, 4.5 to 130). Troponin testing had no significant effect on catheterization incidence (18.2% vs 14.5%; RR, 1.19; 95% CI, 0.72 to 1.92; P>.20) or other outcomes except follow-up echocardiography (13.4% vs 7.4%; RR, 2.24; 95% CI, 1.11 to 4.69; P=.02).

CONCLUSIONS

In a veterans population undergoing cardiac enzyme testing, CKTnI testing led to more ED discharges than CK testing alone but had no effect on inpatient care and was associated with more echocardiograms in a follow-up period.

Medication Safety in Older Adults: Home-Based Practice Patterns

OBJECTIVES

To identify the current state of medication-taking practices of community-dwelling older adults on high-risk medications.

DESIGN

Telephone survey of older adults filling prescriptions for warfarin, digoxin, or phenytoin from May 2, 2002, through June 30, 2003.

SETTING

The Pennsylvania Pharmacy Assistance Contract for the Elderly (PACE) Program, a state-run program providing prescription drug coverage for poor older adults.

PARTICIPANTS

PACE members.

MEASUREMENTS

Patients self-reported sources of information on current medications as well as home-based practices for organizing medication regimens.

RESULTS

Four thousand nine hundred fifty-five PACE members were interviewed. Thirty-two percent of the sample reported that they had not received any specific instructions about their medications, 35% reported that they received instructions from their primary care provider, and 46% indicated they received them from a pharmacist. Fifty-four percent of participants indicated that they used a pillbox for organizing their medications. Older adults prescribed warfarin were more likely to report receiving instructions than those prescribed digoxin or phenytoin.

CONCLUSION

A substantial proportion of older adults on high-risk medications do not recall receiving instructions for the use of their medications and do not take advantage of existing systems for organizing medication regimens. Improved patient education and delivery of medication organization systems are immediate opportunities to potentially reduce the risk of medication errors in older people.

The effect of primary graft dysfunction on survival after lung transplantation

RATIONALE

Primary graft dysfunction is a severe acute lung injury syndrome after lung transplantation. Long-term outcomes of subjects with primary graft dysfunction have not been studied.

OBJECTIVES

We sought to test the relationship of primary graft dysfunction with both short- and long-term mortality using a large registry.

METHODS

We used data collected on 5,262 patients in the United Network for Organ Sharing/International Society of Heart and Lung Transplantation registry between 1994 and 2000. We assessed outcomes in all subjects; to assess potential bias from the effects of early mortality, we also evaluated subjects who survived at least 1 year, using Cox proportional hazards models with time-varying covariates.

MAIN RESULTS

The overall incidence of primary graft dysfunction was 10.2% (95% confidence intervals [CI], 9.2, 10.9). The incidence did not vary by year over the period of observation (p = 0.22). All-cause mortality at 30 days was 42.1% for primary graft dysfunction versus 6.1% in patients without graft dysfunction (relative risk = 6.95; 95% CI, 5.98, 8.08; p < 0.001); among subjects who died by 30 days, 43.6% had primary graft dysfunction. Among patients surviving at least 1 year, those who had primary graft dysfunction had significantly worse survival over ensuing years (hazard ratio, 1.35; 95% CI, 1.07, 1.70; p = 0.011). Adjustment for clinical variables including bronchiolitis obliterans syndrome did not change this relationship.

CONCLUSION

Primary graft dysfunction contributes to nearly half of the short-term mortality after lung transplantation. Survivors of primary graft dysfunction have increased risk of death extending beyond the first post-transplant year.

Role of computerized physician order entry systems in facilitating medication errors

CONTEXT

Hospital computerized physician order entry (CPOE) systems are widely regarded as the technical solution to medication ordering errors, the largest identified source of preventable hospital medical error. Published studies report that CPOE reduces medication errors up to 81%. Few researchers, however, have focused on the existence or types of medication errors facilitated by CPOE.

OBJECTIVE

To identify and quantify the role of CPOE in facilitating prescription error risks.

DESIGN, SETTING, AND PARTICIPANTS

We performed a qualitative and quantitative study of house staff interaction with a CPOE system at a tertiary-care teaching hospital (2002-2004). We surveyed house staff (N = 261; 88% of CPOE users); conducted 5 focus groups and 32 intensive one-on-one interviews with house staff, information technology leaders, pharmacy leaders, attending physicians, and nurses; shadowed house staff and nurses; and observed them using CPOE. Participants included house staff, nurses, and hospital leaders.

MAIN OUTCOME MEASURE

Examples of medication errors caused or exacerbated by the CPOE system.

RESULTS

We found that a widely used CPOE system facilitated 22 types of medication error risks. Examples include fragmented CPOE displays that prevent a coherent view of patients' medications, pharmacy inventory displays mistaken for dosage guidelines, ignored antibiotic renewal notices placed on paper charts rather than in the CPOE system, separation of functions that facilitate double dosing and incompatible orders, and inflexible ordering formats generating wrong orders. Three quarters of the house staff reported observing each of these error risks, indicating that they occur weekly or more often. Use of multiple qualitative and survey methods identified and quantified error risks not previously considered, offering many opportunities for error reduction.

CONCLUSIONS

In this study, we found that a leading CPOE system often facilitated medication error risks, with many reported to occur frequently. As CPOE systems are implemented, clinicians and hospitals must attend to errors that these systems cause in addition to errors that they prevent.

Impact of primary graft failure on outcomes following lung transplantation

STUDY OBJECTIVES

Primary graft failure (PGF) is a severe acute lung injury syndrome that occurs following lung transplantation. We compared the clinical outcomes of patients who developed PGF with those who did not.

METHODS

We conducted a retrospective cohort study including 255 consecutive lung transplant procedures. PGF was defined as (1) diffuse alveolar opacities developing within 72 h of transplantation, (2) an arterial partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio of < 200 beyond 48 h postoperatively, and (3) no other secondary cause of graft dysfunction. PGF was tested for acceptance with 30-day and all-cause hospital mortality rates, overall survival, hospital length of stay (HLOS), duration of mechanical ventilation, and best 6-min walk test (6MWT) distance achieved within 12 months.

SETTING

Academic medical center.

RESULTS

The overall incidence of PGF was 11.8% (95% confidence interval [CI], 7.9 to 15.9%). The all-cause mortality rate at 30 days was 63.3% in patients with PGF and 8.8% in patients without PGF (relative risk [RR], 7.15; 95% CI, 4.34 to 11.80%; p < 0.001). A total of 73.3% of patients with PGF died during hospitalization vs 14.2% of patients without PGF (RR, 5.18%; 95% CI, 3.51 to 7.63; p < 0.001). The median HLOS in 30-day survivors was 47 days in patients with PGF vs 15 days in those without PGF (p < 0.001), and the mean duration of mechanical ventilation was 15 days in patients with PGF vs 1 day in those without PGF (p < 0.001). By 12 months, a total of 28.5% of survivors with PGF achieved a normal age-appropriate 6MWT distance vs 71.4% of survivors without PGF at 12 months (p = 0.014). The median best 6MWT distance achieved within the first 12 months was 1,196 feet in patients with PGF vs 1,546 feet in those without PGF (p = 0.009).

CONCLUSIONS

PGF has a significant impact on mortality, HLOS, and duration of mechanical ventilation following lung transplantation. Survivors of PGF have a protracted recovery with impaired physical function up to 1 year following transplantation.

Patients exposed to rofecoxib and celecoxib have different odds of nonfatal myocardial infarction

BACKGROUND

Studies have postulated that cyclooxygenase-2 (COX-2) selective inhibitors affect cardiovascular risk through various mechanisms. Some of these mechanisms could increase risk (for example, inhibition of prostacyclin production), and some could decrease risk (for example, inhibition of inflammation).

OBJECTIVE

To determine the effect of COX-2 inhibitors on risk for nonfatal myocardial infarction (MI).

DESIGN

Case-control study.

SETTING

36 hospitals in a 5-county area.

PARTICIPANTS

1718 case-patients with a first, nonfatal MI admitted to these hospitals and 6800 controls randomly selected from the same counties.

MEASUREMENTS

Self-reported medication use assessed through telephone interviews.

RESULTS

The adjusted odds ratio for MI among celecoxib users, relative to persons who did not use nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDs), was 0.43 (95% CI, 0.23 to 0.79) compared with 1.16 (CI, 0.70 to 1.93) among rofecoxib users. The use of rofecoxib was associated with a statistically significant higher odds of MI compared with the use of celecoxib (adjusted odds ratio for rofecoxib vs. celecoxib, 2.72 [CI, 1.24 to 5.95]; P = 0.01). Nonselective NSAIDs were associated with a reduced odds of nonfatal MI relative to nonusers. Comparisons of COX-2 inhibitors with nonselective NSAIDs were the following: rofecoxib versus naproxen (odds ratio, 3.39 [CI, 1.37 to 8.40]) and celecoxib versus ibuprofen or diclofenac (odds ratio, 0.77 [CI, 0.40 to 1.48]).

LIMITATIONS

The possibility of recall bias and uncontrolled confounding in this observational study limit the ability to make definitive conclusions. The association of celecoxib with a lower odds of MI could have occurred by chance. Only about 50% of eligible participants completed telephone interviews.

CONCLUSION

Celecoxib and rofecoxib were associated with different odds of MI. Cardiovascular effects among the COX-2 inhibitors seem different, but further studies, preferably randomized trials, are needed to fully understand the spectrum of effects of COX-2 inhibitors and potential differences among them.

Predictors of recall of over-the-counter and prescription non-steroidal anti-inflammatory drug exposure

PURPOSE

Because of the difficulty in establishing a gold standard, data on accuracy of recall of over-the-counter (OTC) medication use are sparse.

METHODS

We studied a cohort of 1889 persons living in the Philadelphia area to assess recall of non-aspirin non-steroidal anti-inflammatory drug (NANSAID) use during the preceding 8 weeks. Our analyses were based on the assumption that among the group of subjects, on average, the reported usage of NANSAIDs should not vary over the previous 8 weeks. To model the effect of time on reported usage while allowing for the inherent correlation of responses within subjects over time, we employed alternating logistic regression.

RESULTS

We documented a significant decline in reported use of OTC NANSAIDs but not prescription NANSAIDs during the 8-week study period (p = 0.3 for frequent prescription NANSAIDs, p = 0.2 for infrequent prescription NANSAIDs, p < 0.001 for frequent OTC NANSAIDs, and p < 0.001 for infrequent OTC NANSAIDs). Reported rates of frequent and infrequent OTC NANSAID consumption declined from 6.3 to 4.6% and from 17.1 to 12.8% between the most recent week and eight weeks prior, respectively.

CONCLUSIONS

Interviews focusing on medications used on an as needed basis should be performed as close as possible to the index date. Likewise, data on frequent use of OTC NANSAIDs may be more reliable than that on infrequent use, particularly when subjects are asked to recall more than a few weeks back in time.

Class effect of angiotensin-converting enzyme inhibitors on prevention of myocardial infarction

Angiotensin-converting enzyme (ACE) inhibitors differ in their affinity for tissue-bound ACE. It has been hypothesized that tissue ACE affinity might be responsible for some of the beneficial cardiovascular properties of ACE inhibitors. The present study examined this question and found no correlation between tissue ACE affinity and risk of first nonfatal myocardial infarction in patients who have hypertension.

Comparative cardiac safety of low-dose thioridazine and low-dose haloperidol

AIM

To compare the rate of ventricular arrhythmia, sudden death and unexplained or unattended death among users of thioridazine and haloperidol.

METHODS

Observational cohort study of thioridazine and haloperidol users in the UK General Practice Research Database (GPRD) using data from 1987 through 29 June 2000. Patients were followed for 30 days following each study prescription. The event of interest was a diagnosis of ventricular arrhythmia, sudden death, or unexplained or unattended death. Cox regression was used to calculate rate ratios (RRs) and 95% confidence intervals (CIs), to examine potential confounding factors, and to examine dose-response relationships.

RESULTS

Use of thioridazine and haloperidol in the GPRD was primarily in older patients, at low dose (median daily dose 31 mg thioridazine, 1.8 mg haloperidol). There was no association between thioridazine use and the rate of ventricular arrhythmia, sudden death, and unexplained or unattended death (adjusted RR 0.9, 95% CI 0.7, 1.1). The rate did not appear to increase with dose for either drug over the range observed.

CONCLUSIONS

These results suggest that low-dose thioridazine and haloperidol have similar cardiac safety.

Comparison of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in the primary prevention of myocardial infarction in hypertensive patients

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have slightly different mechanisms of action. As such, it has been hypothesized that these 2 classes of medications differ in their ability to prevent myocardial infarction. In the present case-control study, we found no difference between angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in the primary prevention of nonfatal myocardial infarction among patients with hypertension.

Plasma leptin levels are associated with coronary atherosclerosis in type 2 diabetes

Leptin signaling may promote atherothrombosis and lead to cardiovascular disease. However, whether leptin is associated with human atherosclerosis, distinct from thrombosis, is unknown. We determined the association of plasma leptin levels with coronary artery calcification (CAC), a measure of coronary atherosclerosis, in a cross-sectional study of type 2 diabetes. Leptin levels were associated with CAC after adjusting for established risk factors [odds ratio (95% confidence interval) for 5 ng/ml leptin increase: 1.31 (1.10-1.55); P = 0.002]. Leptin remained associated with CAC after further controlling for body mass index (BMI) [1.29 (1.07-1.55); P = 0.008], waist circumference [1.30 (1.09-1.57); P = 0.003], C-reactive protein (CRP) levels [1.28 (1.07-1.55); P = 0.008], and subclinical vascular disease [1.30 (1.08-1.57); P = 0.006]. Addition of BMI (P = 0.97), waist (P = 0.55), or CRP (P = 0.39) to a model with leptin failed to improve the model's explanatory power, whereas addition of leptin to a model with BMI (P = 0.029), waist (P = 0.006), or CRP (P = 0.005) improved the model significantly. Plasma leptin levels were associated with CAC in type 2 diabetes after controlling adiposity and CRP. Whether leptin signaling promotes atherosclerosis directly or represents a therapeutic target for the prevention of atherosclerotic cardiovascular disease remains to be explored.

The effects of nonselective non-aspirin non-steroidal anti-inflammatory medications on the risk of nonfatal myocardial infarction and their interaction with aspirin

OBJECTIVES

This study was designed to determine if non-aspirin non-steroidal anti-inflammatory drugs (NANSAIDs) are associated with lower odds of myocardial infarction (MI) and if NANSAIDs, particularly ibuprofen, interfere with aspirin's cardioprotective effect.

BACKGROUND

The NANSAIDs may reduce the risk of MI but may also interfere with aspirin's cardioprotective effect.

METHODS

A case-control study was conducted, with cases of first, nonfatal MI identified prospectively and controls identified randomly from the community.

RESULTS

The use of NANSAIDs was associated with a significant reduction in MI among those not using aspirin (adjusted odds ratio [OR] 0.53; 95% confidence interval [CI]: 0.42 to 0.67). This was true for both ibuprofen (adjusted OR 0.52; 95% CI: 0.39 to 0.69) and naproxen (adjusted OR 0.48; 95% CI: 0.28 to 0.82). Although aspirin itself was associated with decreased odds of MI in those not also using NANSAIDs (adjusted OR relative to no aspirin use 0.79; 95% CI: 0.63 to 0.98), it was not associated with decreased odds of MI among those who were using NANSAIDs (OR 1.28; 95% CI: 0.85 to 1.94; p value for interaction = 0.026). The association of aspirin and reduced odds of MI diminished with increasing frequency of NANSAID use (test for interaction p = 0.006), particularly for ibuprofen (p = 0.018). Among frequent (4 times/week) NANSAID users, the OR for aspirin versus no aspirin was 2.04 (95% CI: 1.06 to 3.94). Users of prophylactic aspirin plus frequent ibuprofen had an OR relative to aspirin-only users of 2.03 (95% CI: 0.60 to 6.84).

CONCLUSIONS

In the absence of aspirin use, NANSAIDs are associated with reduced odds of MI. In those using aspirin, NANSAIDs do not provide additional protection. Additional study is needed to determine the clinical impact of using NANSAIDs along with aspirin for cardioprotection.

Association Between Pulmonary Fibrosis and Coronary Artery Disease

BACKGROUND

Pulmonary fibrosis and atherosclerosis have many similarities at the histopathologic level. Moreover, fibrotic lung diseases exhibit systemic effects and have the potential to affect the vasculature beyond the lung. The existence of a relationship between the two, however, has not been studied.

METHODS

To investigate whether fibrotic lung disorders may predispose to atherosclerosis, we conducted a cross-sectional study of 630 patients referred for lung transplantation evaluation at a university hospital. We compared the prevalence of angiographic coronary artery disease (CAD) in patients with fibrotic vs nonfibrotic lung diseases.

RESULTS

Fibrotic lung diseases were associated with an increased prevalence of CAD compared with nonfibrotic diseases after adjustment for traditional risk factors (odds ratio, 2.18; 95% confidence interval, 1.17-4.06). The magnitude and significance of this association were maintained when only nongranulomatous fibrotic disease or its subset, idiopathic pulmonary fibrosis, was examined. The strength of the relationship between fibrotic disorders and CAD increased when multivessel disease was analyzed (odds ratio, 4.16; 95% confidence interval, 1.46-11.9). No significant association was detected for granulomatous fibrotic disorders (odds ratio, 1.56; 95% confidence interval, 0.47-5.16; P =.47), although this subgroup had fewer cases of CAD for analysis.

CONCLUSIONS

These findings support an association between fibrotic lung disorders and CAD. Further research is necessary to confirm this relationship and to explore the pathologic processes underlying, and potentially linking, these 2 conditions.

Clinical risk factors for primary graft failure following lung transplantation

STUDY OBJECTIVE

s: Primary graft failure (PGF) is a devastating acute lung injury syndrome following lung transplantation. We sought to identify donor, recipient, and operative risk factors for its development.

DESIGN

We conducted a cohort study of 255 consecutive lung transplant procedures performed between October 1991 and July 2000. We defined PGF as follows: (1) diffuse alveolar opacities exclusively involving allograft(s) and developing within 72 h of transplant, (2) a ratio of PaO(2) to fraction of inspired oxygen < 200 beyond 48 h postoperatively, and (3) no other secondary cause of graft dysfunction identified. Risk factors were assessed individually and adjusted for confounding using multivariable logistic regression models.

SETTING

Tertiary-care academic medical center.

RESULTS

The overall incidence was 11.8% (95% confidence interval [CI], 7.9 to 15.9). Following multivariable analysis, the risk factors independently associated with development of PGF were as follows: a recipient diagnosis of primary pulmonary hypertension (PPH; adjusted odds ratio [OR], 4.52; 95% CI, 1.29 to 15.9; p = 0.018), donor female gender (adjusted OR, 4.11; 95% CI, 1.17 to 14.4; p = 0.027), donor African-American race (adjusted OR, 5.56; 95% CI, 1.57 to 19.8; p = 0.008), and donor age < 21 years (adjusted OR, 4.06; 95% CI, 1.34 to 12.3; p = 0.013) and > 45 years (adjusted OR, 6.79; 95% CI, 1.61 to 28.5; p = 0.009).

CONCLUSIONS

Recipient diagnosis of PPH, donor African-American race, donor female gender, and donor age are independently and strongly associated with development of PGF.

One-year clinical outcomes of protected and unprotected left main coronary artery stenting

AIMS

To evaluate outcomes for left main coronary artery (LMCA) stenting and compare results between protected (left coronary grafted) and unprotected LMCA stenting in the current bare-metal stent era.

METHODS

We reviewed outcomes among 142 consecutive patients who underwent protected or unprotected LMCA stenting since 1997. All-cause mortality, myocardial infarction (MI), target-lesion revascularization (TLR), and the combined major adverse clinical event (MACE) rates at one year were computed.

RESULTS

Ninety-nine patients (70%) underwent protected and 43 patients (30%) underwent unprotected LMCA stenting. In the unprotected group, 86% were considered poor surgical candidates. Survival at one year was 88% for all patients, TLR 20%, and MACE 32%. At one year, survival was reduced in the unprotected group (72% vs. 95%, P<0.001) and MACE was increased in the unprotected patients (49% vs. 25%, P=0.005).

CONCLUSIONS

In the current era, stenting for both protected and unprotected LMCA disease is still associated with high long-term mortality and MACE rates. Stenting for unprotected LMCA disease in a high-risk population should only be considered in the absence of other revascularization options. Further studies are needed to evaluate the role of stenting for unprotected LMCA disease.

Adverse events after protamine administration following cardiopulmonary bypass in infants and children

We performed this study to determine the incidence of and risk factors for adverse events (AEs) in infants and children after the IV administration of protamine after cardiopulmonary bypass. In a retrospective cohort study, all relevant anesthesia records from a 3-yr period were examined to identify AEs after protamine. The AEs were then grouped into three categories by applying increasingly strict criteria. Among 1249 anesthesia records, there were no documented episodes of isolated or hypotension-associated right-sided cardiac failure or acute pulmonary dysfunction. The incidence of systemic hypotension after protamine was between 1.76% (95% confidence interval [CI], 1.11%-2.65%) and 2.88% (95% CI, 2.03%-3.97%), depending on the strictness of case definition. To identify risk factors, we performed a nested case-control study in which unmatched controls were randomly selected from the parent cohort at a 4:1 ratio to cases. Cases of hypotension after protamine were more likely during operations on girls (odds ratio [OR], 6.47; 95% CI, 1.66-32.8), after larger doses of protamine (OR, 1.88; 95% CI, 1.03-3.63), or after smaller doses of heparin (OR, 0.49; 95% CI, 0.17-0.67).

IMPLICATIONS

Systemic hypotension after protamine administration occurred in 1.76%-2.88% of pediatric patients having cardiac surgery. Female sex, larger protamine dose, and smaller heparin dose were each associated with increased risk. The development of protamine alternatives or prophylactic therapies may be useful for reducing the frequency of these events.

Effect of antidepressants and their relative affinity for the serotonin transporter on the risk of myocardial infarction

BACKGROUND

Antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), attenuate platelet activation by depleting serotonin storage and may decrease risk of myocardial infarction (MI). These drugs differ in their affinity for the platelet serotonin transporter and therefore may vary in their effects on MI protection.

METHODS AND RESULTS

A case-control study of first MI in patients aged 40 through 75 years was conducted among 36 hospitals in a 5-county area during a 3-year period. Case subjects were patients hospitalized with a first MI, and control subjects were randomly selected from the same geographic area. Detailed information regarding medication use and other clinical and demographic data were obtained by telephone interview. Among the 1080 cases and 4256 controls who participated, there were 223 users of antidepressants with high serotonin transporter affinity, all of which were SSRIs (paroxetine, fluoxetine, and sertraline). After adjustment with multivariable logistic regression for age, gender, race, education, physical activity, quantity of cigarettes smoked per day, body mass index, aspirin use, family history of MI, and history of diabetes, hypertension, or hypercholesterolemia, the odds ratio for MI among current users of antidepressants with high serotonin transporter affinity compared with nonusers was 0.59 (95% CI 0.39 to 0.91; P=0.02). Increasing serotonin transporter affinity was associated with reduced odds of MI among users of all SSRIs (P for trend <0.01) but not tricyclic (P=0.77) or atypical (P=0.70) antidepressants. There was no association detected between non-SSRI antidepressant use and MI.

CONCLUSIONS

Increasing serotonin transporter affinity correlates with greater MI protection with SSRI but not other antidepressant exposure.

Bleeding risk of platelet glycoprotein IIb/IIIa receptor antagonists in broad-based practice (results from the Society for Cardiac Angiography and Interventions Registry)

Randomized trials of platelet glycoprotein (GP) IIb/IIIa receptor inhibitors in patients who have undergone percutaneous coronary intervention (PCI) have shown a modest increase in bleeding risk associated with GP IIb/IIIa inhibitor use. Because clinical trials often enroll highly selected patient populations and are performed in high-volume experienced centers, these results may not apply to a nonclinical trial population, thus altering the risk-benefit ratio of the drugs. Given the widespread use of these agents, we sought to determine bleeding risks in a broad-based population of patients who underwent PCI. We performed a retrospective cohort study of GP IIb/IIIa inhibitors and bleeding in 18,821 procedures from June 1, 1996 to December 31, 1998 using the Society for Cardiac Angiography and Interventions Registry. The primary outcome was bleeding events, defined as clinically significant hematoma formation or hemorrhage. Bleeding risk was 1.9% in the 2,525 patients who received GP IIb/IIIa inhibitors compared with 1.0% in the 16,296 who did not (unadjusted odds ratio [OR] 1.87, 95% confidence interval [CI] 1.35 to 2.59, p <0.001). After adjustment for multiple clinical and procedural variables, the effect was attenuated, with at most a twofold bleeding risk associated with GP IIb/IIIa inhibitor use (adjusted OR 1.39, 95% CI 0.96 to 2.03, p = 0.083). The small increase in absolute risk of bleeding from GP IIb/IIIa inhibitor use in this study is similar to the risk observed in clinical trials. Assuming these agents are as effective as shown in these trials, the risk-benefit ratio of GP IIb/IIIa inhibitors in broad-based PCI practice should be favorable.

Limitations of current risk-adjustment models in the era of coronary stenting

BACKGROUND

Several risk-adjustment models have been developed to compare outcomes of conventional coronary angioplasty across physicians and institutions. Yet the accuracy of these models in contemporary interventional practice--characterized by the widespread use of stents and novel adjuvant pharmacotherapies--has not been sufficiently studied.

METHODS

The principal published predictive models for inhospital mortality after angioplasty were validated in 11,681 patients undergoing coronary stenting and 6475 patients undergoing balloon-only procedures in the Society for Cardiac Angiography and Interventions registry from July 1996 to December 1998. We examined the 2 components of model accuracy: discrimination, as determined by the c-index; and calibration, as measured by the Hosmer-Lemeshow statistic and predicted-versus-observed probability plots.

RESULTS

The discriminative properties of the models were preserved in the validation cohort and did not differ statistically from one another (c-indexes 0.85-0.89). Hosmer-Lemeshow statistics, however, showed poor fit (P <.001), with all 3 models substantially overestimating the risk of adverse outcomes. Although recalibration of the models achieved satisfactory goodness of fit, laboratory-specific ratings differed depending on the model applied.

CONCLUSIONS

Predictive models developed in the era of conventional angioplasty cannot be applied directly to current interventional practice. Although recalibration restores model fit, application of different recalibrated models yields inconsistent assessment of laboratory performance. Development of new, widely generalizable models is warranted, but such models will require continued reassessment as medical technology evolves and practice patterns change.

Hemodynamics and survival in patients with pulmonary arterial hypertension related to systemic sclerosis

STUDY OBJECTIVES

The goal of this study was to determine whether the survival of patients with pulmonary hypertension related to systemic sclerosis (SScPH) was different from that of patients with other forms of pulmonary arterial hypertension.

DESIGN

Retrospective cohort study.

SETTING

Tertiary care medical center.

PATIENTS

Our cohort was composed of 33 patients with pulmonary hypertension that is sporadic, familial, or related to anorexigen use (PPH) and 22 patients with SScPH who underwent initial pulmonary artery catheterization and vasodilator study at our center between January 1997 and June 2001.

MEASUREMENTS AND RESULTS

Patients with SScPH had somewhat lower percentage of predicted lung volumes than patients with PPH (total lung capacity, 80% vs 92%; p = 0.06) and had lower percentage of predicted diffusion capacity of the lung for carbon monoxide (42% vs 68%; p = 0.0002). Right atrial pressure, pulmonary artery pressure, and cardiac index were similar between the groups. Patients with SScPH and PPH were treated with usual medical therapies, such as digoxin, warfarin, and continuous IV epoprostenol. Despite these similarities, the risk of death in patients with SScPH was higher than in patients with PPH (unadjusted hazard ratio, 2.9; 95% confidence interval, 1.1 to 7.8; p = 0.03). This increased risk appeared to persist after adjustment for a variety of demographic, hemodynamic, or treatment variables.

CONCLUSIONS

Despite having similar hemodynamics, patients with SScPH have a higher risk of death than patients with PPH. Future studies of the mechanism and therapy of pulmonary arterial hypertension should focus on the distinctions between the different forms of this disease.

Enhancement of medication recall using medication pictures and lists in telephone interviews

PURPOSE

To determine the effect of reading medication lists and providing medication pictures on recall of non-aspirin non-steroidal anti-inflammatory drugs (NANSAIDs) during telephone interviews in a case-control study.

METHODS

After a series of indication-specific questions, a list of all available NANSAIDs was read to study participants and a series of pictures was reviewed when available. Recall was defined as enhanced if a participant recalled NANSAID use only after the memory aids.

RESULTS

Among the 1484 participants who reported NANSAID use, 94 (6.3%) recalled their NANSAID use only after the memory aids. Several groups demonstrated enhanced recall following the memory aids: men (odds ratio (OR): 1.73; 95% confidence interval (CI): 1.11, 2.69), users of non-prescription versus prescription NANSAIDs (OR 2.28; 95% CI: 1.21, 4.30), those using > 2 other medications (OR 1.69; 95% CI: 1.06, 2.69), those who did not have all of their medication containers available during the interview (OR 1.58; 95% CI: 1.03, 2.42) and cases versus controls (OR 1.90; 95% CI: 1.11, 3.28).

CONCLUSION

The reading of medication names with the availability of medication photographs enhanced recall by approximately 6%. The use of this type of memory aid may reduce recall bias in case-control studies that rely on medication recall, depending on the overall prevalence of medication use and the effect size of the drug on the outcome.

Cardiac arrest and ventricular arrhythmia in patients taking antipsychotic drugs: cohort study using administrative data

OBJECTIVE

To examine the rates of cardiac arrest and ventricular arrhythmia in patients with treated schizophrenia and in non-schizophrenic controls.

DESIGN

Cohort study of outpatients using administrative data.

SETTING

3 US Medicaid programmes.

PARTICIPANTS

Patients with schizophrenia treated with clozapine, haloperidol, risperidone, or thioridazine; a control group of patients with glaucoma; and a control group of patients with psoriasis.

MAIN OUTCOME MEASURE

Diagnosis of cardiac arrest or ventricular arrhythmia.

RESULTS

Patients with treated schizophrenia had higher rates of cardiac arrest and ventricular arrhythmia than controls, with rate ratios ranging from 1.7 to 3.2. Overall, thioridazine was not associated with an increased risk compared with haloperidol (rate ratio 0.9, 95% confidence interval 0.7 to 1.2). However, thioridazine showed an increased risk of events at doses > or =600 mg (2.6, 1.0 to 6.6; P=0.049) and a linear dose-response relation (P=0.038).

CONCLUSIONS

The increased risk of cardiac arrest and ventricular arrhythmia in patients with treated schizophrenia could be due to the disease or its treatment. Overall, the risk with thioridazine was no worse than that with haloperidol. Thioridazine may, however, have a higher risk at high doses, although this finding could be due to chance. To reduce cardiac risk, thioridazine should be prescribed at the lowest dose needed to obtain an optimal therapeutic effect.

Usefulness of the TIMI risk score in predicting both short- and long-term outcomes in the Veterans Affairs Non-Q-Wave Myocardial Infarction Strategies In-Hospital (VANQWISH) Trial

We sought to test the validity and clinical utility of the Thrombolysis In Myocardial Infarction (TIMI) risk score for patients who have non-Q-wave myocardial infarction. A post hoc analysis of the Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) Trial was performed, wherein patients were assigned a TIMI risk score from which both 30-day and 12-month outcomes (death, nonfatal myocardial infarction, or urgent revascularization) were assessed. At 30 days, the TIMI risk score showed a close match between observed and predicted probabilities of events after adjustment for overall event rates. The event rate at 30 days was 6% for a score of 0 to 2, 10% for a score of 3, 13% for a score of 4, and 14% for a score of 5 to 7 (p = 0.003 and c statistic 0.59). Discriminative ability of the score was greater in the conservative group at 30 days (p = 0.0004, c statistic 0.67). The score remained modestly predictive of events at 1 year (c statistic 0.60). Conservative strategy patients had better 30-day outcomes than the invasive strategy patients if their score was 0 to 2 (odds ratio 0.24, 95% confidence interval 0.08 to 0.76). No significant difference in outcomes between strategies was detected for a score > or =3. The TIMI risk score provides moderate incremental prognostic information in high-risk patients, during both short- and long-term follow-up.

Racial differences in the prevalence of cardiac sources of embolism in subjects with unexplained stroke or transient ischemic attack evaluated by transesophageal echocardiography

Little is known about the distribution of cardiac sources of embolism among African-Americans with cryptogenic cerebrovascular events. We compared the prevalence of potential cardiac sources of embolism between black and white patients referred to our laboratory for transesophageal echocardiographic (TEE) evaluation of unexplained stroke or transient ischemic attack. Records were reviewed to exclude subjects with high-risk cardiac or vascular disorders likely to explain the index event. Of 297 patients satisfying the inclusion criteria, 196 were white and 87 black. Potential cardioembolic sources were significantly less common in blacks than in whites (adjusted odds ratio [OR], 0.44; 95% confidence interval [CI] 0.26 to 0.75), and related largely to the difference in prevalence of interatrial communication (OR 0.40; 95% CI 0.21 to 0.74). In contrast, African-Americans had a higher prevalence of left ventricular (LV) hypertrophy (OR 3.50; 95% CI 1.97 to 6.22), and particularly, moderate or severe hypertrophy (OR 4.03; 95% CI 1.88 to 9.65) compared with whites. In conclusion, in African-Americans with unexplained cerebrovascular events, the yield of TEE for potential cardioembolic sources, and especially interatrial communication, is lower than in their white counterparts. African-Americans exhibit a substantially higher prevalence of LV hypertrophy, which may be a marker for a higher burden of subclinical cerebrovascular disease involved in the pathogenesis of cryptogenic cerebral ischemia in this population.

Mortality and adverse events after protamine administration in patients undergoing cardiopulmonary bypass

We designed this study to determine whether adverse hemodynamic events after a protamine administration increase the risk of in-hospital mortality. Using a retrospective cohort study design, medical and anesthesia records of patients undergoing cardiopulmonary bypass (CPB) at the Hospital of the University of Pennsylvania, Philadelphia, between 1990 and 1994 were reviewed. Adverse events after a protamine administration were determined using strict, predefined criteria, and in-hospital mortality was assessed without knowledge of exposure status. Mortality was more frequent among the 53 patients with adverse events (13.2%) than the 223 patients without events (2.7%; crude odds ratio 5.50; 95% confidence interval, 1.49-20.6). After adjusting for confounders, the odds ratio was 6.98 (95% confidence interval, 1.36-35.9; P = 0.017). Those suffering severe events had the highest mortality (23.5% compared with 8.3% among those with less severe events versus 2.7% among those without any event, P = 0.001 for trend). In addition, the odds ratio was largest when using the strictest definition for protamine-related events. In conclusion, patients undergoing CPB who experience adverse events after a protamine administration have an increased risk of in-hospital mortality. Further studies to confirm these findings and development and testing of protamine alternatives or prophylactic therapies are required to determine if mortality can be reduced.

IMPLICATIONS

A retrospective cohort study demonstrated an association between adverse events after a protamine administration and increased in-hospital mortality.

Stress test criteria used in the conservative arm of the FRISC-II trial underdetects surgical coronary artery disease when applied to patients in the VANQWISH trial

OBJECTIVES

We sought to determine whether the stringent stress test criteria for crossover to cardiac catheterization in the conservative arm of the Fast Revascularization During Instability in Coronary Artery Disease (FRISC-II) trial subjected this strategy to a disadvantage by failing to identify patients with surgical coronary artery disease (CAD).

BACKGROUND

In FRISC-II, an invasive strategy provided superior outcomes compared with a conservative strategy for patients with acute coronary syndromes. However, compared with the stress test criteria for crossover to catheterization in the Veterans Affairs Non-Q-Wave Infarction Strategies in Hospital (VANQWISH) trial, the FRISC-II criteria were more restrictive and did not use nuclear imaging or pharmacologic stress testing.

METHODS

We analyzed the conservative arm of VANQWISH to identify the prevalence of surgical CAD in those patients who met the VANQWISH, but not FRISC-II, criteria for catheterization.

RESULTS

Of 385 VANQWISH patients, 90 (23%) met the FRISC-II criteria for catheterization. Another 98 patients (25%) met only VANQWISH stress test criteria (60 patients by exercise and 38 by pharmacologic nuclear stress testing). Among subjects who underwent predischarge angiography, those meeting only VANQWISH stress test criteria had a high prevalence of surgical CAD (51%), comparable to patients who met FRISC-II criteria (54%, p = 0.805).

CONCLUSIONS

The overly stringent risk stratification protocol for conservative-arm patients in FRISC-II could have failed to identify almost as many patients with surgical CAD as it identified. A lower threshold for catheterization in the FRISC-II conservative patients might have improved their outcomes and therefore diminished the putative benefit of an invasive strategy.

Relationship between coronary angioplasty laboratory volume and outcomes after hospital discharge

BACKGROUND

Although an inverse association has been established between short-term complications of percutaneous coronary interventions (PCIs) and the volume of angioplasty procedures performed by catheterization laboratories, no data are available on the association between laboratory volume and long-term outcomes.

METHODS

A cohort study of 25,222 patients undergoing PCI in 43 laboratories in Pennsylvania from October 1994 to December 1995 was performed by use of the Pennsylvania Health Care Cost Containment Council database. The association of laboratory volume with inhospital, 1-month, and 6-month events was estimated by use of multivariable analyses adjusting for patient and procedural characteristics.

RESULTS

Although a higher volume of procedures was associated with reduced inhospital coronary bypass ([CABG] 0.6 odds ratio [OR] for > or =400 vs <400 PCIs/year; 95% CI 0.4, 0.8), it was not associated with CABG occurring within 1 month after discharge (P =.71; OR 1.0, 95% CI 0.6, 1.7). Laboratory volume was also not significantly associated with postdischarge revascularization (PCI or CABG) at 1 month (P =.58; OR 1.1, 95% CI 0.8, 1.4) or 6 months (P =.47; OR 1.04, 95% CI 0.91, 1.19). In addition, laboratory volume was not associated with rates of myocardial infarction (P =.14), death (P =.28), or the combined outcome of PCI, CABG, myocardial infarction, or death (P =.90) at 1 month after hospital discharge.

CONCLUSIONS

Although our study confirmed the volume/complication relationship for inhospital CABG, it did not reveal an association between volume and postdischarge events. These results suggest that inhospital complications will remain the standard for assessing laboratory volume and that selective use of higher-volume laboratories may not improve long-term outcomes.

Parenteral ketorolac and risk of myocardial infarction

PURPOSE

To examine the effects of ketorolac, a non-aspirin non-steroidal anti-inflammatory drug (NANSAID) with antiplatelet properties, on the risk of in-hospital myocardial infarction (MI).

METHODS

A retrospective cohort study was performed among hospitalized patients given 10,219 courses of parenteral ketorolac and patients given 10,145 courses of parenteral opioids, without ketorolac, in 35 hospitals. Patients were matched by hospital, admitting service, and date of study drug initiation. Any MI documented in the chart that occurred during the drug course and up to 3 days after the last dose was recorded by trained abstractors.

RESULTS

MI occurred in 18 (0.2%) ketorolac and 45 (0.4%) opioid courses (odds ratio (OR) 0.40, 95% confidence interval (CI) 0.23-0.69). This negative association persisted in multivariable analysis adjusting for age, sex, history of diabetes mellitus or cardiovascular disease, and administration of antiplatelet agents (OR 0.42; 95% CI 0.24-0.73). The association also persisted in numerous analyses excluding patients who may have been treated with analgesics for ischemic pain, and when restricting events to those occurring while on the drug (OR 0.34; 95% CI 0.17-0.69).

CONCLUSION

These results are consistent with a protective effect of ketorolac against MI. Future research that implements uniform screening for and independent validation of MIs as well as eliminates possible confounding by indication is the next logical step in confirming these findings.

Cigarette yield and the risk of myocardial infarction in smokers

BACKGROUND

Although cigarette smoking is a major risk factor for acute myocardial infarction (MI), cigarette tar yield has not been clearly demonstrated to affect MI risk.

METHODS

A case-control study of first MI in smokers aged 30 through 65 years was conducted among 68 hospitals in an 8-county area during a 28-month period. Case subjects were smokers hospitalized at any of the area hospitals with a first MI. Approximately 4 community control smokers per case subject were randomly selected from the same geographic area using random digit dialing. Detailed data on smoking history and cigarette brand were collected.

RESULTS

We identified 587 case subjects and 2685 controls who smoked cigarettes with known tar yields. After adjustment using multivariable logistic regression, the odds ratios (ORs) for subjects smoking medium- and high compared with low-tar-yield cigarettes were 1.86 (95% confidence interval [CI], 1.21-2.87) and 2.21 (95% CI, 1.47-3.34), respectively. The adjusted OR increased as tar per day intake increased (P<.001 for the trend); compared with the lowest category of tar per day, the ORs (95% CIs) for increasing tar per day were 1.16 (0.83-1.62), 1.85 (1.35-2.52), 2.42 (1.54-3.78), and 2.50 (1.78-3.52). There was a similar trend of increasing ORs as tar per day increased in smokers of lower-yield cigarettes (P<.001 for the trend) and when low-yield cigarette smokers were excluded (P<.001 for the trend).

CONCLUSIONS

Smoking higher-yield cigarettes is associated with an increased risk of MI, and there is a dose-response relationship between total tar consumption per day and MI.

Evaluation of the Society for Coronary Angiography and Interventions' lesion classification system in 14,133 patients with percutaneous coronary interventions in the current stent era

We recently showed that the ACC/AHA coronary lesion classification could be simplified with no loss of predictive value (SCAI I = patent/non-C; SCAI II = patent/C; SCAI III = occluded/non-C; SCAI IV = occluded/C). We now test this system in a database reflecting current stent usage. Data from 14,133 patients with single-native-vessel interventions recorded in the Society for Coronary Angiography and Interventions (SCAI) Registry from July 1996 to July 1999 were analyzed. Stents were used in 60.2% of procedures. Logistic models predicting angiographic success suggested a slight, clinically insignificant preference for the SCAI classification (c-statistic = 0.692 vs. 0.670). Models using clinical variables to predict major complications were superior to models using only lesion classification. Lesion characteristics were related to outcomes primarily in elective (not acute myocardial infarction) patients. In the current PCI device era, the simpler SCAI classification using 7 variables predicted interventional success and complications as well as or better than the ACC/AHA system requiring 26.

Acetaminophen for altering body temperature in acute stroke: a randomized clinical trial

BACKGROUND AND PURPOSE

Mild alterations in temperature have prominent effects on ischemic cell injury and stroke outcome. Elevated core body temperature (CBT), even if mild, may exacerbate neuronal injury and worsen outcome, whereas hypothermia is potentially neuroprotective. The antipyretic effects of acetaminophen were hypothesized to reduce CBT.

METHODS

This was a randomized, controlled clinical trial at 2 university hospitals. Patients were included if they had stroke within 24 hours of onset of symptoms, National Institutes of Health Stroke Scale (NIHSS) score > or =5, initial CBT <3 8.5 degrees C, and white blood cell count < 12 600 cells/mm(3); they were excluded if they had signs of infection, severe medical illness, or contraindication to acetaminophen. CBT was measured every 30 minutes. Patients were randomized to receive acetaminophen 650 mg or placebo every 4 hours for 24 hours. The primary outcome measure was mean CBT during the 24-hour study period; the secondary outcome measure was the change in NIHSS.

RESULTS

Thirty-nine patients were randomized. Baseline CBT was the same: 36.96 degrees C for acetaminophen versus 36.95 degrees C for placebo (P=0.96). During the study period, CBT tended to be lower in the acetaminophen group (37.13 degrees C versus 37.35 degrees C), a difference of 0.22 degrees C (95% CI, -0.08 degrees C to 0.51 degrees C; P=0.14). Patients given acetaminophen tended to be more often hypothermic <36.5 degrees C (OR, 3.4; 95% CI, 0.83 to 14.2; P=0.09) and less often hyperthermic >37.5 degrees C (OR, 0.52; 95% CI, 0.19 to 1.44; P=0.22). The change in NIHSS scores from baseline to 48 hours did not differ between the groups (P=0.93).

CONCLUSIONS

Early administration of acetaminophen (3900 mg/d) to afebrile patients with acute stroke may result in a small reduction in CBT. Acetaminophen may also modestly promote hypothermia <36.5 degrees C or prevent hyperthermia >37.5 degrees C. These effects are unlikely to have robust clinical impact, and alternative or additional methods are needed to achieve effective thermoregulation in stroke patients.

Secondary hypoparathyroidism attributed to hypomagnesemia in a dog with protein-losing enteropathy

Severe hypomagnesemia (0.8 mg/dl; reference range, 1.6 to 2.3 mg/dl), hypocalcemia, and protein-losing enteropathy were identified in a 5-year-old castrated male 3-kg (6.6 lb) Shih Tzu examined because of anorexia, lethargy, paresis, and abdominal distention. Histologic examination of intestinal biopsy specimens revealed lymphangiectasia and lymphocytic, plasmacytic, neutrophilic infiltrates. Initial treatment included administration of magnesium (0.80 mEq/kg [0.36 mEq/lb]) of body weight in a balanced electrolyte solution. This treatment resulted in normalization of the serum magnesium concentration (1.7 mg/dl); resolution of the lethargy, paresis, and tachycardia; and an increase in the serum parathyroid hormone and ionized calcium concentrations. Findings were consistent with secondary hypoparathyroidism attributable to hypomagnesemia. Magnesium concentration should be monitored in all dogs with gastrointestinal tract disease, especially those with protein-losing enteropathy, anorexia, and weakness.

Current research on rapid cycling bipolar disorder and its treatment

Rapid cycling is a pattern of presentation of bipolar disorder that specifies the course of the illness and is associated with a greater morbidity. The validity of rapid cycling as a distinct course modifier for bipolar disorder has been demonstrated and the term has been incorporated into the DSM-IV. The phenomenon of rapid cycling tends to appear late in the course of the disorder, occurs more frequently among females, and is more frequently seen in patients with bipolar type II disorder. Stimulants such as cocaine may also play some role in rapid-cycling. It is generally accepted that a recent history of rapid cycling predicts non-response to monotherapy with lithium and probably carbamazepine as well; however it is also possible that concurrent use of antidepressants may play a role in destabilizing the illness course under these agents. Thus, clinical considerations suggest that discontinuing antidepressants may facilitate the recovery process. Among clinically available monotherapies, valproate and lamotrigine appear to be the most useful clinically. However, other treatments such as lithium, carbamazepine, the atypical antipsychotic agents, thyroid hormone, and bupropion are frequently needed augmentation strategies. Electroconvulsive therapy may also prove efficacious in selected cases. The present paper provides a critical review of the evidence for the foregoing clinical issues in rapid cycling.

Selective serotonin reuptake inhibitors and myocardial infarction

BACKGROUND

Depression is an independent risk factor for myocardial infarction (MI). Selective serotonin reuptake inhibitors (SSRIs) may reduce this risk through attenuation of serotonin-mediated platelet activation in addition to treatment of depression itself.

METHODS AND RESULTS

case-control study of first MI in smokers 30 to 65 years of age was conducted among all 68 hospitals in an 8-county area during a 28-month period. Cases were patients hospitalized with a first MI. Approximately 4 community control subjects per case were randomly selected from the same geographic area using random digit dialing. Detailed information regarding use of antidepressant medication as well as other clinical and demographic data were obtained by telephone interview. A total of 653 cases of first MI and 2990 control subjects participated. After adjustment, using multivariable logistic regression, for age, sex, race, education, exercise, quantity smoked per day, body mass index, aspirin use, family history of MI, number of physician encounters, and history of coronary disease, diabetes, hypertension, or hypercholesterolemia, the odds ratio for MI among current SSRI users compared with nonusers was 0.35 (95% CI 0.18, 0.68; P<0.01). Non-SSRI antidepressant users had a nonsignificant reduction in MI risk with wide confidence intervals (adjusted odds ratio 0.48, CI 0.17, 1.32; P=0.15). However, analysis of this group was limited by the small number of exposed subjects.

CONCLUSIONS

The use of SSRIs may confer a protective effect against MI. This could be attributable to the inhibitory effect SSRIs have on serotonin-mediated platelet activation or possibly amelioration of other factors associated with increased risk for MI in depression.

Incidence and prognostic value of low plasma ionized calcium concentration in cats with acute pancreatitis: 46 cases (1996-1998)

OBJECTIVE

To determine the incidence and prognostic significance of low plasma ionized calcium concentration in cats with clinical signs of acute pancreatitis (AP).

DESIGN

Retrospective study.

ANIMALS

46 cats with AP and 92 control cats with nonpancreatic diseases.

PROCEDURE

Medical records were reviewed, and results of clinicopathologic testing, including plasma ionized and total calcium concentrations, acid-base values, and electrolyte concentrations, were recorded. Cats with AP were grouped on the basis of outcome (survived vs died or were euthanatized), and plasma ionized calcium concentrations, acid-base values, and electrolyte concentrations were compared between groups.

RESULTS

Serum total calcium concentration was low in 19 (41%) cats with AP, and plasma ionized calcium concentration was low in 28 (61%). Cats with AP had a significantly lower median plasma ionized calcium concentration (1.07 mmol/L) than did control cats (1.12 mmol/L). Nineteen (41%) cats with AP died or were euthanatized; these cats had a significantly lower median plasma ionized calcium concentration (1.00 mmol/L) than did cats that survived (1.12 mmol/L). Ten of the 13 cats with AP that had plasma ionized calcium concentrations < or = 1.00 mmol/L died or were euthanatized.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that low plasma ionized calcium concentration is common in cats with AP and is associated with a poorer outcome. A grave prognosis and aggressive medical treatment are warranted for cats with AP that have a plasma ionized calcium concentration < or = 1.00 mmol/L.

Bipolar rapid cycling: focus on depression as its hallmark

The phenomenon of frequent cycling in bipolar disorder was first recognized by Emil Kraepelin in 1913. More recently, rapid cycling has been reported to be a predictor of nonresponse to treatment. At the time of presentation, most patients with DSM-IV-defined rapid cycling appear to be in the depressed phase of their illness. Frequent and more severe episodes of depression appear to be the hallmark of rapid cycling. Reported in this article are recent preliminary data suggesting that the combination of lithium and divalproex sodium administered continuously over 6 months appears to result in marked acute and continuation antimanic efficacy in 85% of patients and marked antidepressant efficacy in 60%. However, only one half of patients experienced bimodal stabilization. Comorbid alcohol, cannabis, and/or cocaine abuse and/or dependence did not appear to directly affect the spectrum of efficacy of lithium and divalproex or response rates in compliant patients. Comorbidity appeared to alter prognosis by increasing the prevalence of poor compliance. The majority of patients receiving lithium and divalproex who required additional treatment were depressed, suggesting that the frequent recurrence of depression is the primary unmet need in patients with rapid cycling. The use of antidepressants in this population has been discouraged because of concerns about the possibility of cycle acceleration. There exists a need for a pharmacotherapy that not only possesses marked acute antidepressant properties, but that does so without inducing switching or cycle acceleration. A double-blind, placebo-controlled trial of lamotrigine monotherapy in bipolar I depression has demonstrated efficacy without causing switching at a rate exceeding placebo; however, this initial study excluded patients with rapid cycling. To explore the efficacy of lamotrigine in rapid cycling, a recent multicenter study has examined lamotrigine as a maintenance therapy for this population. The results indicate that lamotrigine may be a useful treatment for patients with rapid-cycling bipolar II disorder and that this drug has begun to address this unmet need.

Adjustments for center in multicenter studies: an overview

Increasingly, investigators rely on multicenter or multigroup studies to demonstrate effectiveness and generalizability. Authors too often overlook the analytic challenges in these study designs: the correlation of outcomes and exposures among patients within centers, confounding of associations by center, and effect modification of treatment or exposure across center. Correlation or clustering, resulting from the similarity of outcomes among patients within a center, requires an adjustment to confidence intervals and P values, especially in observational studies and in randomized multicenter studies in which treatment is allocated by center rather than by individual patient. Multicenter designs also warrant testing and adjustment for the potential bias of confounding by center, and for the presence of effect modification or interaction by center. This paper uses examples from the recent biomedical literature to highlight the issues and analytic options.

Trial of a novel prostacyclin analog, UT-15, in patients with severe intermittent claudication

Prostacyclin is an endothelially derived vasodilator and inhibitor of platelet aggregation. Despite its therapeutic potential for peripheral arterial disease, the short half-life and chemical instability are barriers to routine therapy. Accordingly, prostacyclin analogs are being evaluated in patients with peripheral arterial disease. State-of-the-art non-invasive ultrasonography allows for serial testing of the hemodynamic effects of vasoactive drugs. The safety, efficacy and hemodynamic effects of UT-15, a novel, long-acting prostacyclin analog, were studied in patients with severe intermittent claudication. A total of eight patients with stable severe intermittent claudication, Fontaine classes IIb-III, were admitted to the hospital for intravenous infusion of UT-15. A symptom-limited, dose-escalation protocol was instituted, beginning with placebo and then with increasing dosage at 60-min intervals, followed by a 2-h period of maintenance dose at the maximum well-tolerated infusion rate. The hemodynamic response in the lower limbs was assessed with serial ultrasonography, segmental arterial pressures and pulse volumes. Blood flow in the common femoral artery increased 29% (p = 0.003) by the end of the maintenance period and remained above baseline throughout the washout period (p = 0.044). Blood velocity in the lower limb increased in most of the peripheral arteries. These increases achieved statistical significance in the common femoral artery (p = 0.025) and anterior tibial artery (p = 0.019), and approached significance in the popliteal artery (p = 0.062). In two of four patients in whom blood flow was undetectable before the infusion, arterial blood flow at the ankle level became apparent on ultrasonography during maintenance infusion. UT-15 infusion improved the pulse volume recording (p = 0.016) but the ankle/brachial index did not change significantly. Common side effects at peak dose included headache and nausea. There were no serious adverse events attributable to UT-15 treatment. In most patients, the optimal infusion rate was 10-20 ng/kg per min. In conclusion, ultrasonography is a novel approach for assessing the hemodynamic response to vasoactive agents. UT-15 is well tolerated when given for up to 2 h and increases arterial blood flow and velocity in patients with severe intermittent claudication.

Evolving methodologies in bipolar disorder maintenance research

BACKGROUND

During the development of a new treatment for bipolar disorder, maintenance studies are used to evaluate the ability of the putative mood stabilizer to prevent relapse and recurrence of further episodes. Comparisons with the early bipolar disorder maintenance studies indicate that the methodologies of recent trials have evolved substantially.

AIMS

To review the methods used in the first- and second-generation maintenance studies, highlighting the differences of the various designs.

METHOD

Literature review.

RESULTS

Methods that have evolved the most include patient enrollment, randomisation schemes and the use of outcome measures and statistical analyses. In addition, regulatory and commercial issues have also influenced study design.

CONCLUSION

There is little consensus on the methodology of bipolar disorder maintenance studies. As the integration of newer therapies into routine clinical practice is dependent on the evidence from controlled studies, it is essential that future maintenance trials in bipolar disorder achieve adequate methodological rigour without sacrificing overall feasibility.