Channeling Bias in the Analysis of Risk of Myocardial Infarction, Stroke, Gastrointestinal Bleeding, and Acute Renal Failure with the Use of Paracetamol Compared with Ibuprofen.

INTRODUCTION: Observational studies estimating severe outcomes for paracetamol versus ibuprofen use have acknowledged the specific challenge of channeling bias. A previous study relying on negative controls suggested that using large-scale propensity score (LSPS) matching may mitigate bias better than models using limited lists of covariates. OBJECTIVE: The aim was to assess whether using LSPS matching would enable the evaluation of paracetamol, compared to ibuprofen, and increased risk of myocardial infarction, stroke, gastrointestinal (GI) bleeding, or acute renal failure. STUDY DESIGN AND SETTING: In a new-user cohort study, we used two propensity score model strategies for confounder controls. One replicated the approach of controlling for a hand-picked list. The second used LSPSs based on all available covariates for matching. Positive and negative controls assessed residual confounding and calibrated confidence intervals. The data source was the Clinical Practices Research Datalink (CPRD). RESULTS: A substantial proportion of negative controls were statistically significant after propensity score matching on the publication covariates, indicating considerable systematic error. LSPS adjustment was less biased, but residual error remained. The calibrated estimates resulted in very wide confidence intervals, indicating large uncertainty in effect estimates once residual error was incorporated. CONCLUSIONS: For paracetamol versus ibuprofen, when using LSPS methods in the CPRD, it is only possible to distinguish true effects if those effects are large (hazard ratio > 2). Due to their smaller hazard ratios, the outcomes under study cannot be differentiated from null effects (represented by negative controls) even if there were a true effect. Based on these data, we conclude that we are unable to determine whether paracetamol is associated with an increased risk of myocardial infarction, stroke, GI bleeding, and acute renal failure compared to ibuprofen, due to residual confounding.

Five-year trends in acetaminophen use exceeding the recommended daily maximum dose.

Temporal patterns of acetaminophen use exceeding the recommended daily maximum dosage of 4 g over a 5-year period (4/1/2011-3/31/2016) were evaluated in an online 1-week diary study of 14 434 adult acetaminophen users who also reported acetaminophen use in the previous month. Specific medications taken were identified by list-based prompting; respondents were not required to know their medications contained acetaminophen. Details of use were recorded daily; total daily dosage was determined programmatically. Prevalence of >4 g use over time was modelled and tested for linear changes. The overall prevalence of >4 g use (6.3% of users and 3.7% of usage days) did not change over the 5 years: odds ratio (OR) persons, 1.02 (95% CI, 0.98-1.09); OR days, 0.98 (0.92-1.05). Deviations from label directions were largely unchanged, though concomitant use increased slightly. Thus, over a recent 5-year period, there was no evidence of change in how often acetaminophen use exceeded the labelled maximum daily dose.

Knowledge of dosing directions among current users of acetaminophen-containing medications.

OBJECTIVES: Users should know the active ingredients and dosing directions to optimize the safe use of acetaminophen-containing medications. The aim of this work was to examine knowledge of acetaminophen-containing medication directions among current users. DESIGN, SETTING, AND PARTICIPANTS: An Internet panel diary study (2012-2016) of 1-week usage of acetaminophen medications (over-the-counter [OTC] and prescription), recorded daily; 9629 participants. Users were asked about ingredients of medications taken; specific dosing instructions were asked for each OTC medication taken. Subjects were considered to be correct only if an accurate response was provided for all of the medications they used. OUTCOME MEASURES: Analyses examined prevalence of several aspects of knowledge and their relation to the corresponding deviations from directions. Knowledge that acetaminophen was an ingredient was compared between medication types. RESULTS: Two-thirds of 5161 participants who used only 1 acetaminophen medication knew the ingredient; the proportion was almost halved in 4468 users of 2 or more. Ingredient knowledge was highest for single-ingredient medications (74%); for combination medications it ranged from 39% (cough or cold) to 61% (sleep or other non-pain). About one-third knew the prohibition against concomitant use of multiple acetaminophen medications; 85% knew the maximum one-time OTC dose, but only 47% knew the minimum interval between doses. Correct knowledge was inversely associated with violating the relevant label directions; in particular, knowing the one-time dose decreased the odds of taking too much at one time fivefold. Knowing both the ingredient and the concomitant use prohibition decreased the odds of concomitant use by 50%. CONCLUSIONS: Knowledge of directions for safe use of acetaminophen-containing medications is poor, and its deficiency is associated with corresponding deviations from label instructions. This study demonstrates a need for education about safe use of acetaminophen-containing medications, particularly for combination products.

Exceeding the maximum daily dose of acetaminophen with use of different single-ingredient OTC formulations.

OBJECTIVES: To assess whether there are differences in the likelihood of exceeding the daily limit of 4 grams of acetaminophen when using different formulations (325 mg, 500 mg, 650 mg) of OTC single-ingredient (SI) acetaminophen medications. DESIGN AND SETTING: Multiyear observational study of acetaminophen use via daily online acetaminophen-usage diaries completed for 7 days. PARTICIPANTS: A total of 7579 U.S. adults from online research panels who used acetaminophen in the month preceding enrollment and used an OTC SI acetaminophen medication during the study. OUTCOME MEASURE: Exceeding the daily dose. RESULTS: On days when 325-mg or 500-mg OTC SI formulations were taken, users were not significantly more likely to exceed 4 grams than on days when OTC SI formulations were not used. On days when 650-mg extended-release (ER) formulations were taken, exceeding 4 grams was significantly more likely (8.9% of days vs. 4.4%; P < 0.0001; median on those days was 5.2 g) than on days with 325- or 500-mg OTC SI formulations. Users of 650-mg ER formulations were significantly less likely to know their dosing interval of 8 hours (33% vs. 49%; P < 0.0001) and more likely to redose too soon (26% vs. 10%; P < 0.0001) and to use other acetaminophen medications concomitantly (14% vs. 7%; P < 0.0001). These patterns were strongest among 650-mg ER products that did not include "8-Hour" in the product name. CONCLUSION: Usage of 500-mg OTC SI acetaminophen formulations does not contribute differently to exceeding dosage compared with other OTC SI acetaminophen formulations. Exceeding 4 grams is more likely when 650-mg ER formulations are used. Improved consumer information on the packages and counseling from pharmacists may help to reduce practices that contribute to exceeding the labeled daily limit of these medications.

Prevalence of exceeding maximum daily dose of paracetamol, and seasonal variations in cold-flu season.

AIMS: To estimate prevalence of excess intake of paracetamol and investigate seasonal variations therein. METHODS: Between 2011 and 2016, 14 481 US adults who used paracetamol in the preceding 30 days were sampled from national online panels and completed a detailed online daily diary of paracetamol medication use for 7 days. Respondents were not told that the study concerned paracetamol. Cold/flu season (CFS), identified using Google Trends data, was contrasted to off-season in symptoms, use of paracetamol medications, and consumption exceeding 4 g (the recommended daily maximum). RESULTS: Overall, 6.3% [95% confidence interval: 5.9-6.7%] of users exceeded 4 g on at least one day; 3.7% [3.5-3.8%] of usage days exceeded 4 g. Cold/flu symptoms were more likely to be experienced and treated with paracetamol in CFS than off-season. Paracetamol users were more likely to exceed 4 g during CFS (6.5% vs. 5.3%; odds ratio = 1.24, 1.04-1.48); days exceeding 4 g also increased (3.9% vs. 2.8%; odds ratio = 1.37, 1.11-1.69). This was not due to differences in characteristics of individuals using paracetamol in CFS, but primarily to increased use of over-the-counter combination medications designed to treat upper respiratory cold/flu symptoms (33.2% of usage days in CFS vs. 24.8% in off-season; odds ratio = 1.58, 1.46-1.72). When such medications were omitted, there was no statistically significant seasonal variation in exceeding 4 g. CONCLUSIONS: Paracetamol use and over-dosing increases in CFS, primarily due to increased use of over-the-counter combinations treating upper respiratory cold/flu symptoms. Pharmacists should warn users to follow labelled dosing directions, especially during CFS.

Exceeding the daily dosing limit of nonsteroidal anti-inflammatory drugs among ibuprofen users.

PURPOSE: Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective and very commonly used, but also have side effects. We determined prevalence of NSAID dosing exceeding the daily limit (EDL) and identified related user characteristics and dosing patterns among current ibuprofen users. METHODS: Online 1-week diary study of 1326 ibuprofen users. NSAIDs were identified by list-based prompting; respondents were not required to know their medications were NSAIDs. Details of hourly use were recorded by respondents daily. Deviations from dosing directions were programmatically determined afterwards. An exit survey obtained information on demographics, medical history, physical and mental health status, attitudes regarding label reading and dosing behavior, and knowledge of product label instructions. RESULTS: Most diary users (90%) took over-the-counter ibuprofen during the week; 37% also took non-ibuprofen NSAIDs. Most did not recognize all products taken as NSAIDs. EDL occurred among 11% of users for ibuprofen, 4% of users for other NSAIDs, and on 9.1% of NSAID usage days. EDL was associated with deviations from detailed dosing directions, particularly exceeding the 1-time dose, which occurred more often with medications with 1-pill doses. Personal characteristics associated with EDL included male sex, ongoing pain, poor physical function, daily smoking, having the attitudes of "choosing my own dose" and not starting with the lowest dose, and poor knowledge of the recommended 1-time and 24-hour doses. CONCLUSIONS: The prevalence of EDL among NSAID users is nontrivial, and it is associated with potentially modifiable factors. Educating consumers about NSAIDs and their dosing directions could reduce excess dosing.

Channeling in the Use of Nonprescription Paracetamol and Ibuprofen in an Electronic Medical Records Database: Evidence and Implications.

INTRODUCTION: Over-the-counter analgesics such as paracetamol and ibuprofen are among the most widely used, and having a good understanding of their safety profile is important to public health. Prior observational studies estimating the risks associated with paracetamol use acknowledge the inherent limitations of these studies. One threat to the validity of observational studies is channeling bias, i.e. the notion that patients are systematically exposed to one drug or the other, based on current and past comorbidities, in a manner that affects estimated relative risk. OBJECTIVES: The aim of this study was to examine whether evidence of channeling bias exists in observational studies that compare paracetamol with ibuprofen, and, if so, the extent to which confounding adjustment can mitigate this bias. STUDY DESIGN AND SETTING: In a cohort of 140,770 patients, we examined whether those who received any paracetamol (including concomitant users) were more likely to have prior diagnoses of gastrointestinal (GI) bleeding, myocardial infarction (MI), stroke, or renal disease than those who received ibuprofen alone. We compared propensity score distributions between drugs, and examined the degree to which channeling bias could be controlled using a combination of negative control disease outcome models and large-scale propensity score matching. Analyses were conducted using the Clinical Practice Research Datalink. RESULTS: The proportions of prior MI, GI bleeding, renal disease, and stroke were significantly higher in those prescribed any paracetamol versus ibuprofen alone, after adjusting for sex and age. We were not able to adequately remove selection bias using a selected set of covariates for propensity score adjustment; however, when we fit the propensity score model using a substantially larger number of covariates, evidence of residual bias was attenuated. CONCLUSIONS: Although using selected covariates for propensity score adjustment may not sufficiently reduce bias, large-scale propensity score matching offers a novel approach to consider to mitigate the effects of channeling bias.

Physician and patient benefit-risk preferences from two randomized long-acting injectable antipsychotic trials.

PURPOSE: To quantify clinical trial participants' and investigators' judgments with respect to the relative importance of efficacy and safety attributes of antipsychotic treatments for schizophrenia, and to assess the impact of formulation and adherence. METHODS: Discrete-choice experiment surveys were completed by patients with schizophrenia and physician investigators participating in two phase-3 clinical trials of paliperidone palmitate 3-month long-acting injectable (LAI) antipsychotic. Respondents were asked to choose between hypothetical antipsychotic profiles defined by efficacy, safety, and mode of administration. Data were analyzed using random-parameters logit and probit models. RESULTS: Patients (N=214) and physicians (N=438) preferred complete improvement in positive symptoms (severe to none) as the most important attribute, compared with improvement in any other attribute studied. Both respondents preferred 3-month and 1-month injectables to oral formulation (P<0.05), irrespective of prior adherence to oral antipsychotic treatment, with physicians showing greater preference for a 3-month over a 1-month LAI for nonadherent patients. Physicians were willing to accept treatments with reduced efficacy for patients with prior poor adherence. The maximum decrease in efficacy (95% confidence interval [CI]) that physicians would accept for switching a patient from daily oral to 3-month injectable was as follows: adherent: 9.8% (95% CI: 7.2-12.4), 20% nonadherent: 25.4% (95% CI: 21.0-29.9), and 50% nonadherent: >30%. For patients, adherent: 10.1% (95% CI: 6.1-14.1), nonadherent: the change in efficacy studied was regarded as unimportant. CONCLUSION: Improvement in positive symptoms was the most important attribute. Patients and physicians preferred LAIs over oral antipsychotics, with physicians showing a greater preference for 3-month over 1-month LAI. Physicians and patients were willing to accept reduced efficacy in exchange for switching a patient from an oral formulation to a LAI.

Seasonality in acute liver injury? Findings in two health care claims databases.

BACKGROUND: Presumed seasonal use of acetaminophen-containing products for relief of cold/influenza ("flu") symptoms suggests that there might also be a corresponding seasonal pattern for acute liver injury (ALI), a known clinical consequence of acetaminophen overdose. OBJECTIVE: The objective of this study was to determine whether there were any temporal patterns in hospitalizations for ALI that would correspond to assumed acetaminophen use in cold/flu season. METHODS: In the period 2002-2010, monthly hospitalization rates for ALI using a variety of case definitions were calculated. Data sources included Truven MarketScan(®) Commercial Claims and Encounters (CCAE) and Medicare Supplemental and Coordination of Benefits (MDCR) databases. We performed a statistical test for seasonality of diagnoses using the periodic generalized linear model. To validate that the test can distinguish seasonal from nonseasonal patterns, we included two positive controls (ie, diagnoses of the common cold [acute nasopharyngitis] and influenza), believed to change with seasons, and two negative controls (female breast cancer and diabetes), believed to be insensitive to season. RESULTS: A seasonal pattern was observed in monthly rates for common cold and influenza diagnoses, but this pattern was not observed for monthly rates of ALI, with or without comorbidities (cirrhosis or hepatitis), breast cancer, or diabetes. The statistical test for seasonality was significant for positive controls (P<0.001 for each diagnosis in both databases) and nonsignificant for ALI and negative controls. CONCLUSION: No seasonal pattern was observed in the diagnosis of ALI. The positive and negative controls showed the expected patterns, strengthening the validity of the statistical and visual tests used for detecting seasonality.

Relation of Health Literacy to Exceeding the Labeled Maximum Daily Dose of Acetaminophen.

INTRODUCTION: Acetaminophen is a commonly used analgesic/antipyretic; overdoses can lead to liver damage. Little is known about the relationship of health literacy to exceeding the recommended maximum daily dose (4 g). METHODS: Subjects were recruited at 23 U.S. malls in 2011. Health literacy was measured by Rapid Estimate of Adult Literacy in Medicine (REALM), classified as very low (VLL, score <45); low (LL, 45-60); or adequate (AL, >60). Participants completed a 7-day acetaminophen use diary by daily telephone interview; an exit interview covered demographics, physical/mental health, medical history, medication label reading, and medication-taking knowledge/attitudes. Acetaminophen products were identified from a comprehensive list; subjects were not required to know their medications contained acetaminophen. Seven hundred fifty-six subjects aged ≥18 years had taken acetaminophen in the past 30 days and completed 7 diary days with ≥1 day of acetaminophen use, plus the exit survey. Analysis was conducted in 2012-2014. RESULTS: VLL were more likely than AL individuals to exceed 4 g on ≥1 day (OR [95% CI]=3.8 [1.5, 9.6]; 4.0 [1.3, 12] after controlling for five REALM score-related factors). On usage days, VLL individuals were also more likely to exceed 4 g (3.3 [1.1, 10], by generalized estimating equations; 2.4 [0.9, 6.6], direct effect after accounting for mediation by other deviations from label recommendations). CONCLUSIONS: VLL individuals exceed the recommended maximum acetaminophen dose more often than AL individuals. Other identified characteristics related to health literacy do not explain this, but it is partly mediated by increased frequency of other label deviations.

Meta-analysis of the effect of an essential oil-containing mouthrinse on gingivitis and plaque.

BACKGROUND: Standard recommendations for oral hygiene practices have focused on mechanical methods (toothbrushing and interdental cleaning). Published evidence indicates antimicrobial mouthrinses provide oral health benefits beyond mechanical methods alone. The purpose of this meta-analysis was to evaluate the combined effectiveness of mechanical methods with essential oil-containing mouthrinses (MMEO) versus mechanical methods (MM) alone in achieving site-specific, healthy gingival tissue and reducing plaque and gingivitis. TYPES OF STUDIES REVIEWED: All industry-sponsored clinical trials investigating the antigingivitis and antiplaque effects of essential oil (EO)-containing mouthrinses conducted from 1980 to 2012 were reviewed; 29 of 32 studies met the inclusion criteria of 6 months or longer duration, randomized, observer-masked, placebo-controlled, and with individual-level site-specific data. By-study treatment effects were estimated through generalized linear models for binary data and analysis of covariance for continuous data, and then combined using standard meta-analysis techniques; heterogeneity was also assessed. RESULTS: Summary odds ratios for a healthy gingival site and for a plaque-free site were, respectively, 5.0 (95% confidence interval [CI], 3.3-7.5) and 7.8 (95% CI, 5.4-11.2) for MMEO participants versus MM participants at 6 months. The summary percentage reductions in whole-mouth mean gingivitis and plaque at 6 months were 16.0 (95% CI, 11.3-20.7) and 27.7 (95% CI, 22.4-32.9), respectively. Responder analyses using aggregate individual-level data showed 44.8% of MMEO participants and 14.4% of MM participants achieved at least 50% healthy sites in their mouths at 6 months. Similarly, 36.9% of MMEO participants and 5.5% of MM participants achieved at least 50% plaque-free sites in their mouths at 6 months. CONCLUSIONS AND PRACTICAL IMPLICATIONS: This is the first meta-analysis to demonstrate the clinically significant, site-specific benefit of adjunctive EO treatment in people within a 6-month period (that is, between dental visits).

Patterns of acetaminophen medication use associated with exceeding the recommended maximum daily dose.

BACKGROUND: Acetaminophen overuse has been linked to liver injury. PURPOSE: To identify patterns of medication use associated with exceeding the recommended daily maximum dose of 4 g acetaminophen. METHODS: Respondents from a national panel completed a detailed daily medication diary online for 7 days (n = 5649), identifying medications taken from a comprehensive list of over-the-counter (OTC) and prescription (Rx) acetaminophen medications. Respondents were not told the study concerned acetaminophen. Total daily intake was calculated from diary data. Generalized estimating equations assessed the association of medication patterns with exceeding 4 g per day among 3618 respondents who used acetaminophen medications (on 13,852 days) during the diary period. RESULTS: Acetaminophen intake exceeded 4 g on 3.1% of usage days; median intake on those days was 5.5 g. As expected, days when intake exceeded 4 g were almost always (92%) marked by deviations from label directions-exceeding the one-time dose, re-dosing too soon, and concomitant use of multiple acetaminophen medications. Re-dosing too soon was the most frequent deviation, and concomitant use was most strongly tied to exceeding the daily limit. Use of both an Rx and an OTC medication on the same day also increased the odds of exceeding 4 g on days when concomitant use occurred. CONCLUSIONS: Excess dosing of acetaminophen is associated with deviations from label directions and by use of both OTC and Rx medications containing acetaminophen within a single concomitant use day.

Prevalence of Chronic Metoclopramide Use and Associated Diagnoses in the US Pediatric Population.

OBJECTIVE: Metoclopramide is the only medication widely used to promote gastrointestinal motility in the USA. Despite its appreciable risk of central nervous system complications, it continues to be prescribed to children for chronic use. We sought to estimate the prevalence of chronic metoclopramide use among US children and identify the diagnoses that may have prompted this use. The US metoclopramide label lists only two indications in adults: symptomatic gastroesophageal reflux (GERD) and diabetic gastroparesis. The latter is rare in children so, in examining the indications likely to have prompted chronic metoclopramide use, we focused on GERD. METHODS: From two health services databases representing privately and publically insured children, respectively, we estimated the number of US children who used metoclopramide chronically and identified the diagnoses recorded at approximately the time when the chronic use began. We defined chronic use liberally as ≥ 35 days' supply, or conservatively as ≥ 130 days' supply in a 6-month period. For each chronic-use definition, insurance type, and age group, we estimated the proportion of children using metoclopramide chronically. We applied these proportions to US population estimates. RESULTS: Under the liberal and conservative definitions, respectively, 89,020 and 28,222 US children used metoclopramide chronically. CONCLUSION: In spite of its risk, substantial numbers of US children use metoclopramide chronically for symptoms suggestive of GERD.

Benefit-risk assessment of rivaroxaban versus enoxaparin for the prevention of venous thromboembolism after total hip or knee arthroplasty.

PURPOSE: Venous thromboembolism is a common complication after major orthopedic surgery. When prescribing anticoagulant prophylaxis, clinicians weigh the benefits of thromboprophylaxis against bleeding risk and other adverse events. Previous benefit-risk analyses of the REgulation of Coagulation in ORthopaedic surgery to prevent Deep vein thrombosis and pulmonary embolism (RECORD) randomized clinical studies of rivaroxaban versus enoxaparin after total hip (THA) or knee (TKA) arthroplasty generally used pooled THA and TKA results, counted fatal bleeding as both an efficacy and a safety event, and included the active and placebo-controlled portions of RECORD2, which might confound benefit-risk assessments. We conducted a post hoc analysis without these constraints to assess benefit-risk for rivaroxaban versus enoxaparin in the RECORD studies. PATIENTS AND METHODS: Data from the safety population of the two THA and two TKA studies were pooled separately. The primary analysis compared the temporal course of event rates and rate differences between rivaroxaban and enoxaparin prophylaxis for symptomatic venous thromboembolism plus all-cause mortality (efficacy events) versus nonfatal major bleeding (safety events). Additionally, these rates were used to derive measures of net clinical benefit, number needed to treat (NNT), and number needed to harm (NNH) for these two end points. RESULTS: After THA or TKA, and compared with enoxaparin, rivaroxaban therapy resulted in more efficacy events prevented than safety events caused, with benefits exceeding harms early and throughout treatment and follow-up. Relative to enoxaparin, rivaroxaban treatment prevented six efficacy events per harm event caused for THA, with NNT =262/NNH =1,711. For TKA, rivaroxaban treatment prevented four to five efficacy events per harm event caused, with NNT =102/NNH =442. Sensitivity analysis that included surgical-site bleeding resulted in NNH =345 for THA and NNH =208 for TKA. CONCLUSION: In the RECORD studies, considering death, symptomatic venous thromboembolism, and major bleeding, rivaroxaban resulted in greater benefits than harms compared with enoxaparin. When incorporating surgical-site bleeding, rivaroxaban also results in greater benefit than harm for TKA and is balanced with enoxaparin for THA.

Prevalence and correlates of exceeding the labeled maximum dose of acetaminophen among adults in a U.S.-based internet survey.

PURPOSE: Acetaminophen is a commonly used analgesic; excessive doses can lead to liver damage. We sought to determine the proportion of acetaminophen users exceeding the recommended maximum daily dose of 4 g and identify correlates of such behavior. METHODS: U.S. adults were recruited from an internet panel in summer 2010, oversampling past 30-day acetaminophen users. Among 47 738 starting the study, 5649 completed all phases; individuals with low education were underrepresented. Subjects completed a 7-day daily diary online, reporting intake of acetaminophen products selected from a comprehensive list; total daily dose was computed from product names. An exit survey elicited: attitudes/knowledge related to product ingredients, label reading, dosing behavior; demographics, medical history, general physical, and mental health status. Unconditional logistic regression identified variables independently associated with use exceeding 4 g. RESULTS: Among 3618 acetaminophen users, 163 took >4 g on ≥1 day (4.5%); the median dose was 5.5 g; 26 took >8 g (0.7%). >4-g users were characterized by chronic pain, poor physical status, and heavy use of medical care. Knowledge of ingredients and recommended OTC doses for all products taken was inversely associated with >4-g use (multivariable odds ratios [ORs] = 0.5-0.6), as was the attitude to start with the lowest dose (OR = 0.6). The attitude that users could choose their own dose was positively associated (OR = 1.3). CONCLUSIONS: The results estimate the proportion of acetaminophen users exceeding 4 g in a group of U.S. adults, identify potentially modifiable attitudes and knowledge associated with such use, and characterize subpopulations at higher risk.

The effect of selective serotonin re-uptake inhibitors on the risk of myocardial infarction in a cohort of patients with depression.

AIM: To evaluate whether selective serotonin re-uptake inhibitor (SSRI) exposure influences the risk of myocardial infarction (MI) in patients with depression. METHODS: This study included 693 patients with MI (cases) and 2772 controls. Conditional logistic regression was used to calculate the odds ratio (OR). RESULTS: SSRI exposure may be associated with a reduced MI risk (OR = 0.77, 95% CI 0.57, 1.03). However, reduced risk was only observed with longer term use (OR = 0.73, 95% CI 0.53, 1.00) and not with shorter term use (OR = 1.15, 95% CI: 0.65, 2.05). CONCLUSIONS: Only longer term use of SSRIs was associated with reduced MI risk, suggesting that other mechanisms, besides an acute anti-platelet effect, may reduce MI risk.

Coronary artery calcification in renal transplant recipients.

Cardiovascular disease is the leading cause of mortality in renal transplant recipients. Although renal transplant recipients frequently undergo cardiac functional tests prior to surgery, coronary atherosclerosis can remain undetected. Coronary artery calcification (CAC), an early marker of atherosclerosis can be quantified using EBCT. The purpose of this study was to determine the extent and characteristics of CAC at the time of renal transplantation. We evaluated 79 consecutive incident asymptomatic renal transplant recipients. Patients were mostly White (62%), male (54%) and had a deceased donor renal transplant (61%). The mean age was 47 (12.1) years. Sixty-five percentage of subjects had CAC. The mean CAC score was 331.5 (562.4) with a median of 43.3. Older age, presence of diabetes, not having a preemptive transplant, deceased donor transplantation and hypercholesterolemia were significantly associated with presence of CAC univariately. Median CAC scores were significantly increased in subjects with diabetes (127.8 vs. 28.9, p=0.05), exposed to dialysis (102.9 vs. 3.7, p<0.001) and deceased donor recipients (169.7 vs. 7.5, p=0.02). Using multiple logistic regression, age and time on dialysis were significantly associated with the presence of CAC at the time of transplant. In summary, CAC is prevalent in patients undergoing kidney transplant. CAC may be a method to identify renal transplant recipients at increased risk for future cardiovascular events.

The relationship between time since registration and measured incidence rates in the General Practice Research Database.

BACKGROUND: The General Practice Research Database (GPRD) is widely used to study incidence rates. This study examines whether incidence rates are overestimated during the first year after registration, how long one needs to wait to obtain accurate incidence rates, and whether the time period of overestimation differs among disease types. METHODS: We measured incidence rates of nine acute, eight chronic, and eight neoplastic outcomes in 3-month intervals through month 36 after enrollment in GPRD. The incidence rates in months 13-36 were used to estimate baseline incidence rates for each diagnosis. RESULTS: For patients registering with practices that were already UTS, incidence rates were highest in the first 3 months after registration. In eight of nine acute diagnoses, the incidence rate was within 20% of baseline by months 4-6; and in seven of eight cancers, the incidence rate was within 20% of baseline by months 7-9. For chronic conditions, the incidence rate in months 10-12 differed from baseline by more than 20% for five of the eight outcomes, respectively. For patients registering prior to UTS, incidence rates during the first quarter were within 20% of baseline for all acute and cancer diagnoses and six of eight chronic diagnoses. CONCLUSIONS: Reported incidence rates are highest in the first 3 months after registration with an UTS practice and decline to baseline over the first year, more quickly for acute conditions than chronic conditions. For patients who registered prior to UTS, incidence rates are near the baseline level at the start of follow-up.

Thromboembolic events with estramustine phosphate-based chemotherapy in patients with hormone-refractory prostate carcinoma: results of a meta-analysis.

BACKGROUND: Combinations of cytotoxic chemotherapy with estramustine phosphate (EMP), a nornitrogen mustard-estrogen conjugate, are used to treat patients with hormone-refractory prostate carcinoma (HRPC). However, thromboembolic events (TE), including deep venous thrombosis (DVT), pulmonary embolism, stroke, myocardial infarction, and arterial thrombosis, are significant toxicities of these regimens. The current study sought to establish the rate of TE and to determine risk factors for TE. METHODS: A MEDLINE-based search identified EMP-based clinical trials published in the English-language peer-reviewed literature after 1990 in which > or = 20 patients with HRPC were enrolled and TE were clearly documented. Patient characteristics and the dose of EMP given were analyzed to determine their association with the rate of TE. RESULTS: Twenty-three studies, enrolling a total of 896 patients, were included in the analysis. The overall risk of TE was 0.07 (95% confidence interval [95% CI], 0.05-0.11). The risk of DVT was 0.06 (95% CI, 0.04-0.09). The risks of all other types of TE were <0.01. Using univariate logistic regression analysis, the dose of EMP administered, baseline patient age, and baseline prostate-specific antigen level were not found to be associated with the total risk of TE. The rates of total TE and DVT may be inflated because one of the analyzed studies initially had a very high rate of DVT (25%) when compared with the others. CONCLUSIONS: The rate of TE in men with HRPC who are treated with EMP-based regimens is significant, but it does not appear to be related to the dose of EMP. Whether TE can be prevented with anticoagulant prophylaxis remains to be determined.

Use of a geographic information system to identify and characterize areas with high proportions of distant stage breast cancer.

A spatial scan statistic was used to search for geographic areas with significantly elevated proportions of women diagnosed with distant stage breast cancer in New Jersey in 1995-1997. The identified areas then were mapped and characterized using data from the 1990 U.S. Census and locations of mammography facilities. These areas' population characteristics included relatively high proportions of black or Hispanic women and linguistically isolated households. Targeted education and screening programs using this information may increase the diagnosis of breast cancer in the early stages, thereby reducing breast cancer mortality.