Drug-Drug Interactions and Their Association with Adverse Health Outcomes in the Older Community-Dwelling Population: A Prospective Cohort Study.

BACKGROUND: Evidence on associations between drug-drug interactions (DDIs) and health outcomes in the older community-dwelling population is limited. OBJECTIVE: We estimate potentially clinically important DDI prevalence and examine the association between DDIs and (1) adverse drug events (ADEs), (2) emergency hospital attendance and (3) health-related quality of life (HRQoL) in an older community-dwelling population in Ireland. METHODS: This is a prospective cohort study of community-dwelling older adults (N = 904) aged ≥ 70 years from 15 general practices in Ireland recruited in 2010 (wave-1) and followed-up over 2 years (wave-2; 2012-2013), with linked national pharmacy claims data. Individuals dispensed two or more drugs (wave-1: N = 842; wave-2: N = 763) were included. DDI prevalence at baseline, follow-up and 6 months prior to each health outcome was estimated. Multi-level regression was used to model the association between DDI-exposure and health outcomes at follow-up. DDI prevalence, adjusted incidence-rate ratios (aIRR), adjusted odds ratios (aOR), ß coefficients and robust standard error (RSE) from multi-level regression analyses, and 95% confidence intervals (CIs) are reported. RESULTS: At wave-1, n = 196 (23.3% [95% CI 20.5-26.3]), individuals were potentially exposed to ≥ 1 DDI, increasing to n = 345 (45.2% [41.7-48.9]) at wave-2. At 2-year follow-up, the median number of ADEs was 3 (interquartile range [IQR 2-5]); 229 (30.1%) had ≥ 1 emergency hospital attendance, and the mean EQ-5D was 0.74 (± 0.23). Evidence for the association between DDI-exposure and emergency hospital attendance at follow-up was lacking (aOR = 1.38 [0.42-4.53]). DDI-exposure was associated with an increasing number of ADEs (aIRR = 1.26 [1.03-1.55]), and decreasing EQ-5D utility (ß = - 0.07, [-0.11 to -0.04], RSE = 0.02). Aspirin-warfarin, clarithromycin-prednisolone, amiodarone-furosemide, clarithromycin-salbutamol, rosuvastatin-warfarin, amiodarone-bisoprolol, and aspirin-nicorandil were common DDIs 6 months preceding these health outcomes. CONCLUSIONS: We found a two-fold increase in DDI prevalence between wave 1 and 2. DDI exposure was associated with increasing ADEs and declining HRQoL at 2-year follow-up. Common DDIs involved anticoagulants, cardiovascular and antimicrobial drugs, which should be targeted for medicine optimisation.

Potentially Inappropriate Prescribing and Potential Prescribing Omissions and Their Association with Adverse Drug Reaction-Related Hospital Admissions.

BACKGROUND: This study aimed to determine the prevalence of potentially inappropriate prescribing (PIP) and potential prescribing omissions (PPOs) and their association with ADR-related hospital admissions in patients aged ≥ 65 years admitted acutely to the hospital. METHODS: Information on medications and morbidities was extracted from the Adverse Drug Reactions in an Ageing Population (ADAPT) cohort (N = 798: N = 361 ADR-related admissions; 437 non-ADR-related admissions). PIP and PPOs were assessed using Beers Criteria 2019 and STOPP/START version 2. Multivariable logistic regression (adjusted odds ratios (aOR), 95%CI) was used to examine the association between PIP, PPOs and ADR-related admissions, adjusting for covariates (age, gender, comorbidity, polypharmacy). RESULTS: In total, 715 (90%; 95% CI 87-92%) patients had ≥1 Beers Criteria, 555 (70%; 95% CI 66-73%) had ≥ 1 STOPP criteria and 666 patients (83%; 95% CI 81-86%) had ≥ 1 START criteria. Being prescribed at least one Beers (aOR = 1.66, 95% CI = 1.00-2.77), or meeting STOPP (aOR = 1.07, 95% CI = 0.79-1.45) or START (aOR = 0.72; 95%CI = 0.50-1.06) criteria or the number of PIP/PPO criteria met was not significantly associated with ADR-related admissions. Patients prescribed certain drug classes (e.g., antiplatelet agents, diuretics) per individual PIP criteria were more likely to have an ADR-related admission. CONCLUSION: There was a high prevalence of PIP and PPOs in this cohort but no association with ADR-related admissions.

Drug-drug interactions and the risk of adverse drug reaction-related hospital admissions in the older population.

AIMS: The aims of this study were to estimate potentially clinically important drug-drug interaction (DDI) prevalence, and the average causal effect of DDI exposure on adverse drug reaction (ADR)-related hospital admission, and to examine differences in health-related quality of life (HRQoL) and length of stay (LOS) per DDI exposure in an older (≥65 years) population acutely hospitalized. METHODS: This was a cross-sectional study conducted among 798 older individuals acutely admitted to hospital in Ireland between 2016 and 2017. Medication (current/recently discontinued/over-the-counter) and clinical data (e.g., creatinine clearance) were available. DDIs were identified using the British National Formulary (BNF) and Stockley's Drug Interactions. Causal inference models for DDI exposure on ADR-related hospital admission were developed using directed acyclic graphs. Multivariable logistic regression was used to estimate the average causal effect. Differences in HRQoL (EQ-5D) and LOS per DDI exposure were examined non-parametrically. DDI prevalence, adjusted odds ratios (aOR), and 95% confidence intervals (CIs) are reported. RESULTS: A total of 782 (98.0%) individuals using two or more drugs were included. Mean age was 80.9 (SD ± 7.5) years (range: 66-105); 52.2% were female; and 45.1% (n = 353) had an ADR-related admission. At admission, 316 (40.4% [95% CI: 37.0-43.9]) patients had at least one DDI. The average causal effect of DDI exposure on ADR-related hospital admission was aOR = 1.21 [95% CI: 0.89-1.64]. This was significantly increased by exposure to: DDIs which increase bleeding risk (aOR = 2.00 [1.26-3.12]); aspirin-warfarin (aOR = 2.78 [1.37-5.65]); and esomeprazole-escitalopram (aOR = 3.22 [1.13-10.25]. DDI-exposed patients had lower HRQoL (mean EQ-5D = 0.49 [±0.39]) compared those non-DDI-exposed (mean EQ-5D = 0.57 [±0.41]), (P = .03); and greater median LOS in hospital (8 [IQR5-16]days) compared those non-DDI-exposed (7 [IQR 4-14] days),(P = .04). CONCLUSIONS: Potentially clinically important DDIs carry an increased average causal effect on ADR-related admission, significantly (two-fold) by exposure to DDIs that increase bleeding risk, which should be targeted for medicine optimization.

Prevalence of Drug-Drug Interactions in Older Community-Dwelling Individuals: A Systematic Review and Meta-analysis.

BACKGROUND: Drug-drug interactions (DDIs) can lead to medication-related harm, and the older population is at greatest risk. We conducted a systematic review and meta-analysis to estimate DDI prevalence and identify common DDIs in older community-dwelling adults. METHODS: PubMed and EMBASE were searched for observational studies published between 01/01/2010 and 10/05/2021 reporting DDI prevalence in community-dwelling individuals aged ≥ 65 years. Nursing home and inpatient hospital studies were excluded. Study quality was assessed using the Joanna Briggs Institute critical appraisal tool. Meta-analysis was performed using a random-effects model with logit transformation. Heterogeneity was evaluated using Cochran's Q and I2. DDI prevalence and 95% confidence intervals (CIs) are presented. All analyses were performed in R (version 4.1.2). RESULTS: There were 5144 unique articles identified. Thirty-three studies involving 17,011,291 community-dwelling individuals aged ≥ 65 years met inclusion criteria. Thirty-one studies reported DDI prevalence at the study-participant level, estimates ranged from 0.8% to 90.6%. The pooled DDI prevalence was 28.8% (95% CI 19.3-40.7), with significant heterogeneity (p < 0.10; I2 = 100%; tau2 = 2.13) largely explained by the different DDI identification methods. Therefore, 26 studies were qualitatively synthesised and seven studies were eligible for separate meta-analyses. In a meta-analysis of three studies (N = 1122) using Micromedex®, pooled DDI prevalence was 57.8% (95% CI 52.2-63.2; I2 = 69.6%, p < 0.01). In a meta-analysis of two studies (N = 809,113) using Lexi-Interact®, pooled DDI prevalence was 30.3% (95% CI 30.2-30.4; I2 = 6.8%). In a meta-analysis of two studies (N = 947) using the 2015 American Geriatrics Society Beers criteria®, pooled DDI prevalence was 16.6% (95% CI 5.6-40.2; I2 = 97.5%, p < 0.01). Common DDIs frequently involved cardiovascular drugs, including ACE inhibitor-potassium-sparing diuretic; amiodarone-digoxin; and amiodarone-warfarin. CONCLUSIONS: DDIs are prevalent among older community-dwelling individuals; however, the methodology used to estimate these events varies considerably. A standardised methodology is needed to allow meaningful measurement and comparison of DDI prevalence.

Evaluating awareness, knowledge and practice of healthcare professionals following implementation of a revised pregnancy prevention programme for isotretinoin in Ireland: A multi-stakeholder cross-sectional study.

PURPOSE: In 2018, following an EU-wide safety review, a revised pregnancy prevention programme (PPP) was introduced for isotretinoin (Roaccutane®). This study aimed to examine awareness, knowledge, and experience implementing the revised isotretinoin PPP in clinical practice across three healthcare professional (HCP) groups in Ireland. METHODS: A cross-sectional study using anonymous online surveys among general practitioners (GPs), community pharmacists, and specialist consultants was undertaken. Descriptive analyses are presented. RESULTS: Across all HCP groups there was high (≥87%) awareness that oral isotretinoin is contraindicated in women of childbearing potential (WCBP) unless the conditions of the PPP are fulfilled, but varying awareness among GPs (54.9%) and community pharmacists (45.9%) that exposure during pregnancy can cause both severe fetal malformations and spontaneous abortions. Implementation of the PPP in clinical practice varied across HCP groups. When initiating isotretinoin in WCBP, 66.7% of specialists and 40.8% of GPs indicated they had considered alternative treatment options, and 71.4% of specialists and 31.6% of GPs reported they first requested a pregnancy test. There was limited provision of the patient reminder card to WCBP, where 26.1% of community pharmacists provide this at each dispensing, while 47.6% of specialists and 11.8% of GPs ensured WCBP had a copy of the card when initiating treatment. Across all HCP groups, there was high (≥81.6%) awareness of the need for urgent consultation and immediate cessation of isotretinoin in the event of an unplanned or suspected pregnancy. CONCLUSIONS: Reinforcement of the provision and utilisation of the isotretinoin patient reminder card may be required, and further targeted education on specific elements of the PPP should be considered for GPs and community pharmacists.

Valproate utilisation trends among women of childbearing potential in Ireland between 2014 and 2019: A drug utilisation study using interrupted time series.

PURPOSE: This study aimed to examine trends in valproate use among women of childbearing potential (WCBP) aged 16-44 years in Ireland following two European-directed regulatory interventions in December 2014 and April 2018. METHODS: This was a repeated cross-sectional study using monthly national pharmacy claims data, to examine trend changes in the prevalence of valproate use among WCBP pre and post two separate regulatory events in December 2014 and April 2018. Annual population estimates from the Central Statistics Office were used to calculate the prevalence rate per 1000 eligible women. Segmented regression analysis of interrupted time series with negative binomial regression was used to examine rates for WCBP aged 16-44 years, and by 10-year age groups. Prevalence ratios (PR) are presented with 95% confidence intervals (CIs). RESULTS: Among WCBP aged 16-44 years, there was no statistically significant change in the month-to-month prevalence ratio in the post- compared to pre-December 2014 intervention period. A significant decline was, however, observed in the post-, compared to pre-April 2018 intervention period (PR = 0.998, [95% CIs: 0.996, 1.000]; p = 0.029). Among those aged 16-24 years, a significant decreasing trend in the month-to-month prevalence ratio was found in the post- compared to pre-December 2014 intervention period (PR = 0.991, [95% CIs: 0.984, 0.998];p <0.01). A marginal effect was observed in the post- compared to pre-April 2018 intervention period for those aged 25-34 years (PR = 0.996, [95% CIs: 0.992, 1.000]; p = 0.048). CONCLUSION: Although no evidence of change was observed following the December 2014 intervention period, a significant decline in the prevalence ratio of valproate use was observed after the 2018 intervention, which may reflect the introduction of the most recent contraindication measures.

Prevalence and Factors Associated with Potential Drug-Drug Interactions in Older Community-Dwelling Adults: A Prospective Cohort Study.

BACKGROUND: Older patients are at increased risk of drug-drug interactions (DDIs) due to polypharmacy. Cardiovascular and central nervous system (CNS) drugs are commonly implicated in serious DDIs. OBJECTIVES: This study aimed to determine the prevalence and factors associated with potential 'severe' cardiovascular and CNS DDIs among older (≥ 70 years) community-dwellers. METHODS: This was a prospective cohort study using linked data from a national pharmacy claims database and waves 1 and 2 of The Irish LongituDinal study on Ageing (TILDA). 'Severe' cardiovascular and CNS DDIs were identified using the British National Formulary 77 and Stockley's Drug Interactions. The prevalence of 'severe' DDIs (any DDI vs. none) was calculated. Logistic regression was used to examine the association between sociodemographic, functional ability, and medication-related factors and the risk of DDI exposure between waves 1 and 2. RESULTS: A total of 1466 patients were included [mean age (standard deviation) = 78 (5.5) years; female n = 795, 54.2%]. In total, 332 community-dwellers aged ≥ 70 years [22.65%, 95% confidence interval (CI) 20.58-24.86] were potentially exposed to at least one 'severe' cardiovascular or CNS DDI, with more than half (54.82%) of this cohort dispensed the same DDI for a prolonged time (≥ 3 consecutive claims). Aspirin-warfarin was the most frequently dispensed (co-prescribed) DDI (n = 34, 10.24%, 95% CI 7.39-14.00), followed by atorvastatin-clarithromycin (n = 19, 5.72%, 95% CI 3.64-8.81). Polypharmacy [≥ 10 vs. < 5 drugs, odds ratio (OR) 13.40, 95% CI 8.22-21.85] and depression (depressed vs. not, OR 2.12, 95% CI 1.34-3.34) were significantly associated with these DDIs, after multivariable adjustment. CONCLUSION: 'Severe' cardiovascular and CNS DDIs are prevalent in older community-dwellers in Ireland, and those with polypharmacy and depression are at a significantly increased risk.

Awareness, knowledge and practice of healthcare professionals following implementation of a Pregnancy Prevention Program for sodium valproate in Ireland: a multi-stakeholder cross-sectional study.

OBJECTIVES: To establish awareness, knowledge, use and experience in practice of a sodium valproate pregnancy prevention program (PPP) in Ireland ("prevent") among three healthcare professional (HCP) groups. METHODS: A cross-sectional study using anonymous online surveys was conducted among general practitioners (GPs), pharmacists, and specialist consultants. Descriptive analyses are presented. RESULTS: HCP response rates were 5.8% for GPs (90/1544), 10.7% for pharmacists (219/2052), and 7.6% for specialists (17/224). Across HCP groups, there was high awareness (>90%) for specialist referral when female valproate patients are planning pregnancy, or become pregnant, but less awareness to refer annually for specialist review. While awareness of a possible teratogenic effect at any stage of pregnancy was high (>80%), most GPs (62.2%, 95% CI: 51.3, 71.9%) and community pharmacists (53.1%, 95% CI: 43.2, 62.8%) were unsure of the magnitude of risk for developmental disorders, while most specialists under-estimated this risk (46.7%, 95% CI: 24.8, 69.9%). Although >70% of the respondents identified valproate to be contraindicated in any woman of childbearing potential unless the conditions of the PPP are fulfilled, experience implementing key elements in practice varied. CONCLUSIONS: Our findings suggest continued effort is needed to ensure optimal implementation of "prevent" into clinical practice in Ireland.