Persistent Use Research Articles

The market lifecycle of duloxetine for urinary incontinence in Norway

To investigate the epidemiology of prescriptions for duloxetine for the treatment of stress urinary incontinence during its entire lifecycle in Norway (October 2004-May 2007), including the persistence of use of the drug and the prescribers. Observational study in Norway. All prescriptions on duloxetine filled in Norwegian pharmacies. Data from the Norwegian Prescription Database. Patient's age, unique identification, date of dispensing, data on specialty of the prescribing doctor, and number of packages purchased. Persistence of use of duloxetine was analyzed by grouping the months of first prescription filled into quarters of a year, from the fourth quarter of 2004 to the third quarter of 2007. A total of 3,024 filled prescriptions were recorded of which 2,903 (96%) could be further analyzed, corresponding to 37 users per 100,000 women in the population. Each patient filled a mean of 3.4 prescriptions. The persistence of use was very low from the second quarter itself, and after 1 year only 12.5% of the patients still purchased the drug. Most prescriptions were written by GPs and gynecologists. A prescription database like ours consists of dispensed prescriptions and not drugs taken. We believe that these biases are of little importance for the main results. Analyses from the national prescription database show that duloxetine had a low uptake on the market and a low persistence rate among the patients during its full lifecycle on the Norwegian market.

Contrasting Trajectories of Heroin, Cocaine, and Methamphetamine Use

ABSTRACT Current literature has shown that heroin addiction is characterized by long periods of regular use persisting over the life course, whereas the course of stimulant use is less understood. The current study examined long-term trajectories of drug use for primary heroin, cocaine (crack/powder cocaine), and methamphetamine (meth) users. The analyses used data from five studies that collected longitudinal information using the Natural History Instrument, including 629 primary heroin users, 694 cocaine users, and 474 meth users. Drug use trajectories over the 10 years since initiation demonstrated the persistence of use over time for all three drugs, with heroin use at the highest level (13 to 18 days per month), cocaine at the lowest level (8 to 11 days), and meth in between (approximately 12 days per month). Application of growth mixture models revealed five distinctive groups: Consistently High Use (n = 545), Increasing Use (n = 260), Decreasing Use (n = 254), Moderate Use (n = 638), and Low Use (n = 100). Heroin users were disproportionately overrepresented in the Consistently High Use group and underrepresented in the Low Use group; cocaine and meth users were mostly in the Moderate Use group. Users in the High Use group also had earlier onsets of drug use and crime, longer incarceration durations, and were the least employed. Clinical/service policy and practice need to recognize and adapt to the specific patterns and needs of users of different drugs while being mindful of the stage drug users are at in their life course.

Using Computer-Based Decision Support to Close the “Know–Do” Gap in Lipid-Lowering Therapy

A strange paradox haunts our attempts to prevent ischemic heart disease. Medicine has addressed the relation between serum lipids and atherosclerosis through a series of scientific triumphs. First, epidemiology demonstrated the association between abnormal cholesterol levels and coronary artery disease. Then, physiology and biochemistry elucidated the pivotal role of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in the synthesis of lipoproteins. Next, pharmacology led to the development of new medications to target that enzyme without the often-unbearable side effects of earlier drugs. And finally, clinical researchers enrolled tens of thousands of patients at hundreds of centers worldwide to prove the efficacy of these treatments and help guide their use. Taken together, these steps represent one of the finest examples of the application of science to understand and ameliorate human disease. Article p 371 But shifting our focus from the successful laboratory or clinical trial site to the population reveals more disappointing data. We physicians fail to diagnose potentially dangerous lipid levels in up to a third of our patients with cardiovascular disease1,2; when the problem is identified, we often do not properly deploy the impressive arsenal of treatments that have been put in our hands. In the United States, fewer than half of those who would benefit from lipid-modifying treatment for coronary heart disease risk reduction are receiving it.3 And of those on therapy, just half of patients actually achieve their cholesterol goals.4 This results in part from poor persistence by physicians in monitoring lipid levels and adjusting therapy accordingly, as well as poor persistence by patients in staying with their prescribed regimens for both economic and noneconomic reasons.5 In summary, despite the wealth of tools available to diagnose and manage this common condition, only a fraction of people who have it are being adequately treated. The …

Persistence With Once-Daily Versus Twice-Daily Bupropion for the Treatment of Depression in a Large Managed-Care Population

In this study, the impact of dosing frequency [once daily with bupropion extended-release (XL) versus twice daily with bupropion sustained-release (SR)] on medication persistence was assessed over a 9-month period in a large cohort of patients with depression in a managed-care setting. Administrative claims data from the Integrated Health Care Information Services National Managed Care Benchmark database were analyzed for patients 18 to 64 years old with a documented diagnosis of depression who began treatment with bupropion XL or SR between September 2003 and February 2004. Persistence of use was higher with once-daily bupropion XL (n = 1074) than with twice-daily bupropion SR (n = 1917) across measures assessed by univariate tests of proportions. The mean (+/-SD) number of days between the first and last prescription claims was longer with bupropion XL (128.37 +/- 103.46 days) than with bupropion SR (82.31 +/- 96.86 days) (P < 0.0001). The bupropion XL cohort had higher persistency of use than the bupropion SR cohort (mean +/- SD = 0.47 +/- 0.38 versus 0.30 +/- 0.36) (P < 0.0001) and a higher medication possession ratio (mean +/- SD = 0.50 +/- 0.33 versus 0.36 +/- 0.31) (P < 0.0001). Medication persistency >0.7 and a medication possession ratio >0.7 were almost twice as likely in the bupropion XL cohort (38.5% and 32.0%, respectively) than in the bupropion SR cohort (21.5% and 17.0%, respectively). Results of multivariate analyses adjusted for age, gender, and index date support the univariate analyses. Because better persistence and adherence may be associated with less likelihood of relapse and lower depression-associated health care utilization and economic burden, health care providers should consider the potential benefits of initiating treatment with bupropion XL for bupropion candidates and for switching bupropion SR recipients to treatment with bupropion XL.

Tolerability, quality of life, and persistency of use in patients with glaucoma who are switched to the fixed combination of latanoprost and timolol

This study was undertaken to assess tolerability, quality of life, and persistency of use and to monitor changes in intraocular pressure (IOP) during the first 6 mo after a switch to fixed combination latanoprost/timolol. In Germany, 271 general ophthalmology practices enrolled patients who were switched from previous ocular hypotensive therapies to latanoprost/timolol for medical reasons. Usual care routines were followed, and IOP was measured at baseline and approximately 6 mo later. Adverse events were recorded throughout. Immediately before switching and at follow-up, patients completed a 29-item quality-of-life questionnaire. Of 1052 patients who met analysis criteria, 748 (71%) switched from combination therapy and 304 (29%) from monotherapy. An insufficient IOP reduction with the previous therapy was a reason for switching in 71% of patients; the desire to simplify to once-daily administration was cited in 66%. Ocular adverse events were reported in 19 patients after the switch, and 97% remained on therapy throughout the follow%up period. After switching, patients were less likely to forget to instill their eyedrops or to feel that their drops had adverse effects; they found it easier to include eyedrop administration in their routine; they were more satisfied with the frequency of instillation; and they were more likely to want to continue with the drops. Across all previous therapies, mean IOP decreased from 20.6+/-3.7 mm Hg to 17.2+/-2.8 mm Hg after the switch (P<.001)-a 14.8% difference. Fixed combination latanoprost/timolol is well tolerated and effective in patients who are switched from other monotherapies or combination therapies for medical reasons. Such a switch may be associated with improved quality of life.

Analysis of genetic correlations between multivariate measures of lactation persistency and somatic cell score in Italian Simmental cattle

Genetic relationships between lactation curve traits and Somatic Cell Count are of great interest for dairy cattle breeding. Factor Analysis (MFA) and Principal Component Analysis (PCA) can be used to extract from the correlation matrix of milk test day records new unobservable (latent) variables that can be related to lactation curve shape. Previous researches report that MFA is particularly able to extract two latent variables related with level of production in early lactation (PEL) and lactation persistency (PERS), respectively, whereas PCA yields a leading component related to the average level of production (AVY) for the whole lactation and a second component negatively related with tests of early lactation and positively with tests of the second part of lactation (SLOPE). Aim of this work was to estimate genetic correlations between lactation curve shape traits and Somatic Cell Score (SCS). MFA and PCA were carried out on a data set of 16,020 lactations of Italian Simmental cows, each with six TD records for milk yield recorded with the A4 scheme. Genetic parameters were estimated with a bivariate animal model that included fixed effects of herd-test date, parity*age*lactation stage (only parity*age for lactation curve traits), calving season, and random effects of additive genetic and permanent environment. Heritability estimates were moderate for lactation curve traits (0.15, 0.15, 0.21 and 0.09 for PEL, PERS, AVY and SLOPE, respectively) and low for SCS (0.09). Correlations between lactation curve traits and SCS were favourable, i.e. negative, except for the level of production in early lactation. In particular, the genetic improvement of lactation persistency result in a contemporary reduction of SCS (rg -0.55 and -0.51 with PERS and SLOPE, respectively) whereas the increase of level of production in early lactation can lead to a moderate increase of SCS (rg 0.13). Finally, the two measures of persistency could be used for different selection strategies: the use of PERS may allow for the increase of persistency together with the total lactation yield whereas the use of SLOPE may result in an improvement of the lactation curve shape without modifying total lactation yield.

Persistence of drug use during imprisonment: relationship of drug type, recency of use and severity of dependence to use of heroin, cocaine and amphetamine in prison

To investigate the persistence of use of heroin, cocaine and amphetamine drugs during imprisonment, and to identify factors associated with increased levels of persistence. The use of heroin, cocaine and amphetamine by current prison inmates has been examined and, in particular, the relationship between drug use within prison and the type of drug used prior to imprisonment, recency of use and severity of dependence. A randomly selected sample of 1009 adult male prisoners in 13 prisons in England and Wales during 1994/95; structured confidential interviews conducted by independent research staff. Enquiry about prior use of heroin, cocaine or amphetamine focused on three time-periods (ever, last year and last month pre-prison) and the use of these drugs during the first month of imprisonment. A total of 557 (55%) of the 1009 prisoners had used previously one of the three drugs selected for study: 58% had used heroin, 69% cocaine and 75% amphetamine. More than half (59%; 327/557) had used these drugs in the month before the current imprisonment. Drug use in prisons was most likely to occur among those who had used in the month prior to imprisonment. The persistence of heroin use in prison occurred more frequently (70%) than use of cocaine (20%) or amphetamine (15%). Of those using heroin pre-imprisonment, 67% considered they were dependent, compared to 15% and 22%, respectively, for cocaine and amphetamine users. Changes in the drug-taking behaviour of drug users after imprisonment vary according to the type of drug being taken. Prisoners were much more likely to continue to use heroin than either cocaine or amphetamines while in prison. Heroin was most likely to be used by those who had been using heroin during the immediate pre-imprisonment period, and particularly by the two-thirds of heroin users who considered themselves dependent. In view of the high prevalence of prior use of these drugs by individuals currently imprisoned, continuing attention is required to study of their behaviour and of the impact of interventions that may be introduced during or following their incarceration.

How Should We Measure Medication Adherence in Clinical Trials and Practice?

Abstract and poster presented at the Annual Scientifi c Ses-sions of the American Heart Association, Orlando, Florida, November 2003. References Avorn J, Monette J, Lacour A, et al. 1998. Persistence of use of lipid-lower-ing medications: a cross-national study. JAMA , 279:1458–62.therapy in elderly patients. JAMA , 288:455–61.Botelho RJ, Dudrak R. 1992. Home assessment of adherence to long-term medication in the elderly. J Fam Pract , 35:61–5.Choo PW, Rand CS, Inui TS, et al. 1999. Validation of patient reports, automated pharmacy records, and pill counts with electronic monitoring of adherence to antihypertensive therapy. Med Care , 37:846–57.Christensen DB, Williams B, Goldberg HI, et al. 1997. Assessing compli-ance to antihypertensive medications using computer-based pharmacy records. Med Care , 35:1164–70.Craig HM. 1985. Accuracy of indirect measures of medication compliance in hypertension. Res Nurs Health , 8:61–6.Cramer JA, Mattson RH, Prevey ML, et al. 1989. How often is medica-tion taken as prescribed? A novel assessment technique.

Heroin maintenance for chronic heroin dependents.

Dependent heroin users are characterised by the persistence of use in spite of the difficulties they experience with health, law, social achievements and personal relationships. The present review will consider maintenance treatment in which the patients enter programs of pharmacological administration tailored to achieve patient stabilisation. Many medications have been used for this purpose such as: Methadone, Buprenorphine and LAAM. The present review will focus on maintenance treatment through the prescription of heroin. To assess the efficacy and acceptability of heroin maintenance versus methadone or other substitution treatments for opioid dependence, in retaining patients in treatment; reducing the use of illicit substances and improving health and social functioning. The Cochrane Central Register of Trials (CENTRAL) issue 4, 2002; MEDLINE (on Silver Platter) 1966-2002; EMBASE (on OVID) 1980-2000 and CINAHL till 2000 were searched. There was no language or publication year restrictions. Many researchers were contacted for information. Randomised controlled trials of heroin (alone or combined with methadone) maintenance treatment compared with any other pharmacological treatments. The trials were independently assessed for inclusion and methodological quality by the reviewers. Data were extracted independently and double checked. Studies were not pooled together because of heterogeneity. 2400 references were obtained and 20 studies were eligible, 4 met the inclusion criteria for a total of 577 patients. The studies included could not be analysed cumulatively because of heterogeneity of interventions and outcomes considered. Two studies compared injected heroin to oral methadone for 1 year (270 patients) but considered different outcomes; one study compared injected heroin and methadone to oral methadone for 6 months (51 patients); and one compared inhaled heroin and methadone to oral methadone for 1 year (235 patients). Retention in treatment: in two studies there was no statistical difference between groups; one study (N=90) had a RR=2.49 (95% CI 1.51-4.10) in favour of heroin; one study (N=235) had a RR 0.79 (95%CI 0.68-0.90) in favour of methadone. Relapse to illegal heroin use, based on self report: in one study the proportion of people still using heroin were 64% in the heroin group, 59% methadone group; in the other study the RR was 0.33 (95%CI 0.15-0.72) in favour of heroin. The remaining studies did not provide the data. Criminal offence: one of the two studies which provided details about this showed the potential of heroin prescription in reducing the risk of being charged RR 0.32 (95% CI 0.14-0.78). Social functioning: the two studies reporting this outcome did not show statistical difference between intervention groups. The two most recent studies considered criminal offence and social functioning as part of a multidomain outcome measure and showed higher improvement among those treated with heroin plus methadone over those on methadone only. No definitive conclusions about the overall effectiveness of heroin prescription is possible because of non-comparability of the experimental studies available to be included in this review. Results favouring heroin treatment come from studies conducted in countries where the treatment system is comprehensive and easy accessible Methadone Maintenance Treatment at effective dosages is available. In those studies heroin prescription was addressed to patients who had failed previous methadone treatments.

Long-term persistence in use of statin therapy in elderly patients

ContextKnowledge of long-term persistence with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) therapy is limited because previous studies have observed patients for short periods of time, in closely monitored clinical trials, or in other unrepresentative settings.ObjectiveTo describe the patterns and predictors of long-term persistence with statin therapy in an elderly US population.Design, Setting, and PatientsRetrospective cohort study including 34 501 enrollees in the New Jersey Medicaid and Pharmaceutical Assistance to the Aged and Disabled programs who were 65 years of age and older, initiated statin treatment between 1990 and 1998, and who were followed up until death, disenrollment, or December 31, 1999.Main Outcome MeasuresProportion of days covered (PDC) by a statin in each quarter during the first year of therapy and every 6 months thereafter; predictors of suboptimal persistence during each interval (PDC <80%) were identified using generalized linear models for repeated measures.ResultsThe mean PDC was 79% in the first 3 months of treatment, 56% in the second quarter, and 42% after 120 months. Only 1 patient in 4 maintained a PDC of at least 80% after 5 years. The proportion of patients with a PDC less than 80% increased in a log-linear manner, comprising 40%, 61%, and 68% of the cohort after 3, 12, and 120 months, respectively. Independent predictors of poor long-term persistence included nonwhite race, lower income, older age, less cardiovascular morbidity at initiation of therapy, depression, dementia, and occurrence of coronary heart disease events after starting treatment. Patients who initiated therapy between 1996-1998 were 21% to 25% more likely to have a PDC of at least 80% than those who started in 1990.ConclusionsPersistence with statin therapy in older patients declines substantially over time, with the greatest drop occurring in the first 6 months of treatment. Despite slightly better persistence among patients who began treatment in recent years, long-term use remains low. Interventions are needed early in treatment and among high-risk groups, including those who experience coronary heart disease events after initiating treatment.

Comparison of effectiveness and safety of simvastatin in patients

Because subjects aged >65 years actually experienced a greater benefit in terms of absolute risk reduction than younger persons in the statin trials,1–3 it is reasonable to consider very elderly patients for secondary prevention when a reasonable quality of life can be expected over the next 3 to 5 years.4 Pending the results of ongoing studies specifically addressing the value of statin therapy in the elderly, we examined the efficacy and persistence of use of simvastatin in the secondary prevention patients aged ≥75 years versus those aged <75 years in the computerized database of 1 clinic in our large, private cardiology practice.

Long-term persistence in use of statin therapy in elderly patients.

Knowledge of long-term persistence with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) therapy is limited because previous studies have observed patients for short periods of time, in closely monitored clinical trials, or in other unrepresentative settings. To describe the patterns and predictors of long-term persistence with statin therapy in an elderly US population. Retrospective cohort study including 34 501 enrollees in the New Jersey Medicaid and Pharmaceutical Assistance to the Aged and Disabled programs who were 65 years of age and older, initiated statin treatment between 1990 and 1998, and who were followed up until death, disenrollment, or December 31, 1999. Proportion of days covered (PDC) by a statin in each quarter during the first year of therapy and every 6 months thereafter; predictors of suboptimal persistence during each interval (PDC <80%) were identified using generalized linear models for repeated measures. The mean PDC was 79% in the first 3 months of treatment, 56% in the second quarter, and 42% after 120 months. Only 1 patient in 4 maintained a PDC of at least 80% after 5 years. The proportion of patients with a PDC less than 80% increased in a log-linear manner, comprising 40%, 61%, and 68% of the cohort after 3, 12, and 120 months, respectively. Independent predictors of poor long-term persistence included nonwhite race, lower income, older age, less cardiovascular morbidity at initiation of therapy, depression, dementia, and occurrence of coronary heart disease events after starting treatment. Patients who initiated therapy between 1996-1998 were 21% to 25% more likely to have a PDC of at least 80% than those who started in 1990. Persistence with statin therapy in older patients declines substantially over time, with the greatest drop occurring in the first 6 months of treatment. Despite slightly better persistence among patients who began treatment in recent years, long-term use remains low. Interventions are needed early in treatment and among high-risk groups, including those who experience coronary heart disease events after initiating treatment.

Initiation and continuation of newer antiretroviral treatments among medicaid recipients with AIDS

To examine initiation of newer antiretroviral treatments across sociodemographic subgroups during the 3 years following the introduction of these treatments, and explore persistence on treatment and its association with patient characteristics. Merged Medicaid paid claims and HIV/AIDS surveillance data were used to analyze use of protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) over time. Survival analysis techniques were used to analyze initiation of PI/NNRTI use. Ordinary least squares and logistic regression were used to determine predictors of persistence on PI/NNRTI therapy. The study population consisted of 2,459 New Jersey non-HMO adult Medicaid beneficiaries with AIDS, identified through a match between HIV/AIDS Registry and Medicaid files. Their PI/NNRTI use was followed from March 1996, when the first PI was licensed, to the end of 1998. African Americans initiated treatment on average 8 months later than non-Hispanic whites; initiation of treatment was also slower for injection drug users and for those who did not receive case management through a Medicaid waiver program. These bivariate findings were confirmed with a multivariate time-to-treatment analysis using proportional hazards regression. Among those initiating PI/NNRTI use, 35% had discontinued it by the end of follow-up. Bivariate analyses of treated individuals found that PI/NNRTI use as a proportion of follow-up time was lower for African Americans and Hispanics, and higher for older individuals and for those receiving case management through a Medicaid waiver program, while injection drug use history was not associated with persistence. These findings were confirmed by a regression analysis, which found that controlling for other characteristics, African-American race, and Hispanic ethnicity were each associated with a significant 8% reduction in the proportion of time on PI/NNRTIs following initiation of treatment. Alternative approaches for modeling persistence produced similar results. Results suggest that consistent longitudinal use is difficult for many patients. Persistence of use was lower for minority beneficiaries despite comparable coverage for pharmacy and other health services through Medicaid. Our findings suggest the need to examine nonfinancial barriers to appropriate use of highly active antiretroviral therapy, and to develop and test programmatic strategies for supporting patients in remaining on these regimens consistently.

Predictors of persistence of use of the novel antidiabetic agent acarbose.

A carbose is the first of a new class of antidiabetic agents, the alpha-glucosidase inhibitors. This study characterizes and identifies predictors of persistence of use of acarbose. Medical, pharmaceutical, and demographic records were extracted for 2 cohorts of patients (social assistance recipients and seniors) from the databases of Quebec's provincial health plan. Patients were eligible for inclusion if they had received their first dispensation of acarbose between August 1, 1996, and December 31, 1997. The observation period included at least 1 year before the first dispensation and a minimum of 4 months after. New users of acarbose included 216 social assistance recipients and 677 seniors who were followed up for 82 914 and 270 041 person-days, respectively. Median persistence with acarbose treatment was 83 days (95% confidence interval, 75-105 days) for social assistance recipients and 105 days (95% confidence interval, 90-119 days) for seniors. In both cohorts, treatment by an endocrinologist vs another physician predicted longer treatment persistence. In the seniors cohort, additional determinants of (earlier) treatment discontinuation included a higher initial daily dose, previous treatment with insulin, and consultation with a gastroenterologist after treatment initiation. New users of acarbose showed low persistence in 2 cohorts of beneficiaries of Quebec's provincial health plan. Prescribing specialist was an important predictor of persistence in seniors and the socially assisted. The importance of 4 additional factors in seniors only led to hypotheses concerning population differences in treatment expectations and in the occurrence and tolerance of adverse effects.

Predictors of Long-term Persistence on Statins in a Subsidized Clinical Population

Objectives The use of statins in primary prevention of cardiovascular disease is currently under debate. This study characterizes and identifies predictors of the persistence of use of statins in a clinical cohort of subsidized new users of similar age to the WOSCOPS trial subjects. Methods Medical, pharmaceutical, and demographic records for the period January 1, 1987 through December 31, 1994 were extracted from the databases of Québec's provincial health plan for a 10% random sample of social assistance recipients. Patients remained eligible for inclusion if they had received a first dispensation of a statin between January 1, 1987 and July 31, 1994. Persistence was defined as the number of days on treatment with a statin while continuing to renew dispensations within a defined time limit. Results New users of statins included 983 social assistance recipients who were observed for a total of 2,439,153 person-days. Median persistence on statin treatment was 173 (95% CI = 155, 204) days. Only 13% of patients persisted for 5 years of treatment. A higher index of chronic morbidity, pre-existing cardiovascular disease, and previous use of nicotinic acid were predictive of longer persistence on statin medication. Those patients whose first statin dispensation was for lovastatin discontinued treatment earlier than those whose first dispensation was for pravastatin or simvastatin. Conclusion New users showed low persistence on statins in a cohort of socially assisted persons aged 45–64, in spite of the minimal financial cost of the drug for such beneficiaries of Québec's provincial health plan.

Types of marijuana users by longitudinal course.

Taxonomies of alcoholism and antisocial behaviors based on developmental course converge on two-group classifications that emphasize early and late onset. Typologies for users of illicit drugs remain to be developed. This article proposes a developmental taxonomy of marijuana users. Cluster analysis was applied to a representative community sample of 708 (364 male, 344 female) marijuana users followed from adolescence to age 34-35. The Ward method, followed by relocation, was used to classify marijuana users into different types based on age of onset, chronicity of heavy use and persistence of use. ANOVA and logit analyses were utilized to describe the cluster solution and examine the correlates of cluster membership. Four marijuana use clusters were identified: early onset-heavy use, early onset-light use, mid onset-heavy use and late onset-light use. The groups differed from each other in degree of involvement in marijuana and other drugs, sociodemographic and lifestyle characteristics. The majority of those with early onset did not become heavily involved in marijuana. Unique factors were associated with membership in each group. Factors differentiating early from mid-onset heavy use included association with marijuana-using peers and having had a mental disorder. Peer delinquency was an additional factor differentiating early initiators who became heavy users from those who did not. A simple two-type classification fails to take into account the heterogeneity of early and late onset groups. By itself, early onset into marijuana will not lead to problematic use or rapid progression into the use of other drugs. Motivation underlying use and dysfunctional behaviors are associated with the development of problematic drug use and dependence.

Persistence of use of lipid-lowering medications: a cross-national study.

Although clinical trials have demonstrated the benefits of lipid-lowering therapy, little is known about how these drugs are prescribed or used in the general population. To estimate predictors of persistence with therapy for lipid-lowering drug regimens in typical populations of patients in the United States and Canada. A cohort study defining all prescriptions filled for lipid-lowering drugs during 1 year, as well as patients' demographic and clinical characteristics. New Jersey's Medicaid and Pharmacy Assistance for the Aged and Disabled programs and Quebec's provincial medical care program. All continuously enrolled patients older than 65 years who filled 1 or more prescriptions for lipid-lowering drugs (N = 5611 in the US programs, and N = 1676 drawn from a 10% sample in Quebec). Proportion of days during the study year for which patients had filled prescriptions for lipid-lowering drugs; predictors of good vs poor persistence with therapy. In both populations, patients failed to fill prescriptions for lipid-lowering drugs for about 40% of the study year. Persistence rates with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors were significantly higher than those seen with cholestyramine (64.3% vs 36.6% of days with drug available, respectively). Patients with hypertension, diabetes, or coronary artery disease had significantly higher rates of persistence with lipid-lowering regimens. In New Jersey, multivariable analysis indicated that the poorest patients (those enrolled in Medicaid) had lower rates of drug use than less indigent patients (those enrolled in Pharmacy Assistance for the Aged and Disabled) after adjusting for possible confounders, despite virtually complete drug coverage in both programs. When rates of use were measured in the US population for the 5 years following the study year, only 52% of surviving patients who were initially prescribed lipid-lowering drugs were still filling prescriptions for this drug class. In all populations studied, patients who were prescribed lipid-lowering drug regimens remained without filled prescriptions for over a third of the study year on average. Rates of persistence varied substantially with choice of agent prescribed, comorbidity, and socioeconomic status, despite universal coverage of prescription drug costs. After 5 years, about half of the surviving original cohort in the United States had stopped using lipid-lowering therapy altogether.

Nicotine gum use and outcome in a general practitioner intervention against smoking

In a general practitioner intervention against smoking (employing nicotine chewing gum) smokers who used more than a box of gum were, prior to the intervention, more motivated to quit smoking and more dependent than those who did not use more than a box. They were also older. Even after controlling for demographic, dependence, motivational and previous success factors, those who used more than a box of gum had a significantly enhanced probability of success compared with other smokers. Although causal conclusions cannot be drawn from these analyses, stress on the importance of persistence in use of the gum is recommended.

Changes in drug behavior from the middle to the late twenties: initiation, persistence, and cessation of use.

Patterns of initiation, persistence, and cessation of use of licit, illicit, and prescribed drugs are presented for a longitudinal cohort from their middle to the late twenties. The cohort is representative of adolescents formerly enrolled in public secondary high schools in New York State. No additional initiation of cigarettes, alcohol, and illicit drugs occurred in the four-year follow-up interval, except for cocaine and pills. The largest proportional increase of new users occurred for prescribed psychoactive drugs. Alcohol showed the most persistence of use, followed by cigarettes and marijuana. As the cohort ages, those who continue to use illicit drugs actively do so at lower levels of intensity than at younger ages. For each drug class, the persistence of use is strongly related to earlier intensity of involvement. By age 29, men have accumulated almost twice as many months of use of illicit drugs as women.