Incident Users Of Antidepressants Research Articles

Concomitant medication use and its implications on the hazard pattern in pharmacoepidemiological studies: example of antidepressants, benzodiazepines and fracture risk

Background: Antidepressants and benzodiazepines are often co-prescribed and both associated with an increased fracture risk, albeit with distinctive hazard patterns. Timing of initiation of one with respect to the other and duration of use may influence the combined fracture hazard.
 The objective of our study was to describe patterns of concomitant use of benzodiazepine and antidepressants in terms of timing of initiation and duration and to illustrate the potential impact of various scenarios of timing of co-use on hip fracture hazard.
 Methods: Patients initiating antidepressant therapy (2002-2009) were identified from the Netherlands Primary Care Research Database. Concomitant benzodiazepine use was assessed according to the start time of benzodiazepine with respect to antidepressant therapy start. Duration of concomitant use was estimated relative to the length of antidepressant treatment episode. 
 Results: Among 16,087 incident antidepressant users, 39.0% used benzodiazepines concomitantly during their first antidepressant treatment episode. The time of initiation of benzodiazepine use was variable (64.4% starting before, 13.7% simultaneous and 21.9% after antidepressants). Duration of concomitant use in the three groups varied. 
 Conclusions: Co-prescribed medications with a common adverse event, may not only require accounting for concomitant use, but also the timing of start and duration of use as the overall hazard may vary accordingly.

PMH34 LONG-TERM UTILIZATION OF ANTIDEPRESSANT DRUGS: PREVALENCE AND ASSOCIATED FACTORS

Antidepressant drugs consumption has risen in recent years driven by longer treatment duration. The objective of this study was to measure the prevalence of log-term use of antidepressants among incident antidepressants users in the Bologna area, Italy, and to identify main determinants. We conducted a retrospective claims-based cohort study by using the Bologna Local Health Authority data. A cohort of 18,307 incident users of antidepressants in 2013 was selected and subjects were followed for three years. Long-term use was defined as having at least one prescription for antidepressants claimed in each year of the follow-up and chronic use as claiming at least 180 defined daily doses per year. Factors associated with chronic and long-term use were identified by univariate and multivariate logistic regressions. 5448 (29.8%) and 1817 (9.9%) subjects were long-term and chronic users, respectively. Older age, polytherapy with antidepressants, polypharmacy (>5 drugs claimed) and being prescribed the first antidepressant by a hospital physician, were independently associated with chronic and long-term use. Sex was not a determinant. Antidepressant drugs long-term use is common in our population. Because longer treatments should be clinically motivated, these results strongly encourage the need to assess actual appropriateness as they may indicate potentially inappropriate prescription patterns.

Antidepressant switching patterns in the elderly.

A cohort study of medication supply data from 6011 aged care residents in 60 long-term care facilities was conducted. Incident antidepressant users were followed for 12 months and their patterns of antidepressant use determined. The type of switching from and to different antidepressant classes was determined according to National and International recommendations for antidepressant switching. In total, 11% (n = 44) of the residents were initiated on an antidepressant medication (n = 402) switched to a different antidepressant agent within 12 months. Residents commenced on a SNRI or TCA were most likely to switch antidepressants (17% in each group). Almost half of the switches (n = 21, 48% of all switches) were not implemented according to guideline recommendations. Direct switch and taper followed by wash out and switch, accounted for all of the inappropriate switching (29% and 71%, respectfully), with half occurring to mirtazapine (N = 7) or from mirtazapine (N = 3). Over one in 10 long-term aged care residents who commence an antidepressant will switch to a different antidepressant within 12 months. Current antidepressant switching practices in long-term residential aged care may be increasing the risk of harm associated with antidepressant switching, with around half of all switches not following current guideline recommendations.

Risk of head and traumatic brain injuries associated with antidepressant use among community-dwelling persons with Alzheimer\u2019s disease: a nationwide matched cohort study

BackgroundAntidepressant use has been associated with an increased risk of falling, but no studies have been conducted on whether antidepressant use is associated with an increased risk of head injuries which often result from falling among older persons. The objective of this study was to investigate the risk of head and brain injuries associated with antidepressant use among community-dwelling persons with Alzheimer’s disease.MethodsA matched cohort study was conducted by comparing new antidepressant users (n = 10,910) with two matched nonusers (n = 21,820) in the MEDALZ study cohort. The MEDALZ cohort includes all community-dwelling persons newly diagnosed with Alzheimer’s disease between 2005 and 2011 in Finland. Incident antidepressant users were identified based on register-based dispensing data from the Prescription register with a 1-year washout period for antidepressant use. Nonusers were matched with users based on age, gender, and time since Alzheimer’s disease diagnosis. The outcome events were defined as any head injuries and traumatic brain injuries based on diagnoses in Hospital Discharge and Causes of Death registers. Propensity score adjusted Cox proportional hazard models were utilized. Sensitivity analyses with case-crossover design were conducted. All registers are linkable with unique personal identification numbers assigned for each resident.ResultsAntidepressant use was associated with an increased risk of head injuries (age-adjusted event rate per 100 person-years 2.98 (95% confidence interval (CI) 2.49–3.06) during use and 2.43 (95% CI 2.06–2.35) during nonuse, adjusted hazard ratio (HR) 1.35, 95% CI 1.20–1.52) and traumatic brain injuries (age-adjusted event rate per 100 person-years 1.33 (95% CI 1.13–1.53) during use and 1.10 (95% CI 1.00–1.20) during nonuse, adjusted HR 1.26, 95% CI 1.06–1.50). The risk was highest during the first 30 days of use (HR 1.71, 95% CI 1.10–2.66 for head injuries; HR 2.06, 95% CI 1.12–3.82 for traumatic brain injuries) and remained at an elevated level for head injuries for over 2 years of use. In case-crossover analyses, antidepressant use was consistently associated with a higher risk of head injuries.ConclusionsAntidepressant use was associated with an increased risk of the most severe outcomes, head and brain injuries, in persons with Alzheimer’s disease. Antidepressant use should be carefully considered and the association confirmed in future studies.

Impact of socioeconomic position and distance on mental health care utilization by incident users of antidepressants. A Danish nationwide follow-up study

IntroductionEqual access to health care treatment is a highly prioritized goal in most OECD countries. Timely access has become a priority too; in Denmark now with a 4-week deadline from referral to diagnosis. When mental health services become more centralized and allocation of patients to treatment further away from home become more common, it could have a negative impact on the goal of equal access.ObjectiveTo determine the impact of socioeconomic position (SEP) and distance to provider on outpatient mental health care utilization among incident users of antidepressants.MethodA nationwide, Danish, register based, follow-up study on frequencies of contacts to out-patient psychiatric services, psychologist consultations supported by public funding and therapeutic talks by general practice.Preliminary resultsOutpatient-psychiatric services were reached more often by patients in low SEP measured by income, but their frequencies of visits were less. Contacts to psychologists were less than half for patients in low SEP and less frequent too. Mental health service by GP showed low SEP associated with low contact. No difference in use of emergency or inpatient psychiatric services was found. Distance to provider showed interaction with SEP and contact to psychologist and frequencies of contact to outpatient psychiatrists. When distance increased by 5 km, contact to psychologist fell by 11% among lowest income group and frequencies of visits to outpatient psychiatrist fell by 5%.Preliminary conclusionLower SEP is associated with lower mental health care utilization. Increased distance to provider increases inequity in mental health service utilization.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Antidepressant adherence patterns in older patients: use of a clustering method on a prescription database

According to the World Health Organization, depression will become the second most important cause of disability worldwide by 2020. Our objective was to identify patterns of adherence to antidepressant treatments in older patients using several indicators of adherence and to characterize these patterns in terms of medication exposure. We conducted a retrospective cohort study using the French National Health Insurance reimbursement database. Incident antidepressant users aged more than 65 were included from July 1, 2010, to June 30, 2011, and followed up for 18 months. Antidepressant and other psychotropic drugs (opioids, benzodiazepines, antipsychotics, anti-epileptics) were recorded. Adherence to antidepressant treatment was assessed by several measures including proportion of days covered, discontinuation periods, persistence of treatment, and doses dispensed. Patients were classified according to their adherence patterns using a mixed clustering method. We identified five groups according to antidepressant adherence. One group (n = 7505, 26.9%) was fully adherent with regard to guidelines on antidepressant use. Two patterns of nonadherent users were identified: irregular but persistent users (n = 5131, 18.4%) and regular but nonpersistent users (n = 9037, 32.4%). Serotonin reuptake inhibitors were the most frequently dispensed antidepressant class (70.6%), followed by other antidepressants (43.3%, mainly serotonin-norepinephrine reuptake inhibitors and tianeptine) and tricyclic antidepressants (TCAs) (13.4%). Nonadherent users more frequently had a dispensing of TCA, opioid, and anti-epileptic medication than adherent users. Health policies to improve adherence to antidepressant treatment may require better training of physicians and pharmacists, insisting on the important role of the continuation period of antidepressant treatment.

Antidepressant use and the risk of suicide: A population-based cohort study

BackgroundThe existing literature provides contradictory evidence on antidepressant use and risk of suicide. Some studies have shown that the use of Selective Serotonin Reuptake Inhibitors (SSRIs) is associated with an increased risk of suicide, especially during the first months of treatment, whereas other studies did not confirm this association. For this reason, our objective was to investigate the association between antidepressant use and risk of suicide in incident antidepressant users in relation to time since starting therapy. MethodsWe conducted a population-based cohort study within the Dutch Integrated Primary Care Information (IPCI) database, in incident users of antidepressant therapy between 1994 and 2012 (n=27,712). Cox proportional hazard models were used to study the association between current use of SSRIs, tricyclic antidepressants (TCA) and other antidepressants and risk of suicide or attempted suicide. ResultsDuring follow-up, a total of 280 incident antidepressant users attempted or committed suicide. Current use of SSRIs (hazard ratio (HR): 0.78, 95% CI: 0.57–1.07), TCAs (HR: 0.82, 95% CI: 0.48–1.42) or other antidepressants (HR: 0.75, 95% CI: 0.47–1.18) was not statistically significantly associated with suicide compared to past use of any of the antidepressants. LimitationsAlthough a large healthcare database was used, the number of reported cases of suicide (attempt) was low. ConclusionsThis study did not indicate an increase in risk of suicide after starting treatment with SSRIs, TCAs or other antidepressants compared with past antidepressant use.

PMH15 - Risk of hyponatremia among the incident users of antidepressants

Newer antidepressants selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) are the most commonly prescribed antidepressants. This is due mostly to their better side effect profile when compared to older drugs like tricyclic antidepressants (TCAs). However these classes are not completely bereft of side effects. Hyponatremia is a condition in which the serum sodium level falls below normal; it has been proposed this occurrence is associated with the binding affinity to the 5-HT receptor. The objective of our study is to compare the incidence of hyponatremia among the newer classes of antidepressants. We used a cohort study design using Lifelink claims data to compare the incidence of hyponatremia in TCAs, SSRIs, and SNRIs. Incidence was reported per 10,000 person-years. Cox model was used to assess the risk of adverse events while adjusting for potential confounders. A total of 314,796 patients with an incident prescription for a TCA, SSRI, or SNRIs were identified and met study inclusion criteria. The unadjusted hazard ratio for hyponatremia in patients on SSRIs was 0.789 (C.I=0.729-0.854) and on SNRIs was 1.112 (C.I=0.976-1.268) when compared to TCAs. However, after adjusting for covariates using the Cox model the hazard ratios were found to be 1.013 (C.I=0.934-1.099) for SSRIs and 1.069 (C.I=0.937-1.221) for SNRIs again compared to TCAs. After doing stepwise regression to remove covariates that did not have significant effect the results remained similar, 1.017(C.I=0.939-1.101) for SSRIs and 1.074 (C.I=0.941-1.225) for SNRIs. No significant increase in the risk of hyponatremia for SSRIs or SNRIs over TCAs was found. The covariates we identified show significant interaction with hyponatremia. However, the results must be interpreted with caution as the ICD-9 code that identifies hyponatremia has been shown to have a sensitivity below 30%, thus our analysis potentially excludes a large number of cases.

An electronic health record driven algorithm to identify incident antidepressant medication users.

ObjectiveWe validated an algorithm designed to identify new or prevalent users of antidepressant medications via population-based drug prescription records.Patients and methodsWe obtained population-based drug prescription records for the entire Olmsted County, Minnesota, population from 2011 to 2012 (N=149 629) using the existing electronic medical records linkage infrastructure of the Rochester Epidemiology Project (REP). We selected electronically a random sample of 200 new antidepressant users stratified by age and sex. The algorithm required the exclusion of antidepressant use in the 6 months preceding the date of the first qualifying antidepressant prescription (index date). Medical records were manually reviewed and adjudicated to calculate the positive predictive value (PPV). We also manually reviewed the records of a random sample of 200 antihistamine users who did not meet the case definition of new antidepressant user to estimate the negative predictive value (NPV).Results161 of the 198 subjects electronically identified as new antidepressant users were confirmed by manual record review (PPV 81.3%). Restricting the definition of new users to subjects who were prescribed typical starting doses of each agent for treating major depression in non-geriatric adults resulted in an increase in the PPV (90.9%). Extending the time windows with no antidepressant use preceding the index date resulted in only modest increases in PPV. The manual abstraction of medical records of 200 antihistamine users yielded an NPV of 98.5%.ConclusionsOur study confirms that REP prescription records can be used to identify prevalent and incident users of antidepressants in the Olmsted County, Minnesota, population.

Antidepressant Utilization in British Columbia From 1996 to 2004: Increasing Prevalence but Not Incidence

Antidepressant Utilization in British Columbia From 1996 to 2004: Increasing Prevalence but Not Incidence