Trends in prescription medicine use by older people in New Zealand 2010- 2015: a national population-based study.

BACKGROUND: Research investigating trends in the general prescription medicine use of older people in New Zealand is limited. AIM: To examine trends in the use of outpatient medicines by older adults and assess changing patterns in use from 2010 to 2015. METHODS: A retrospective cohort study including all New Zealand primary care patients over 65 years of age utilising data from the national pharmaceutical claims database. We calculated the prevalence of use within three age groups and by sex in each year by anatomical therapeutic class, therapeutic group and individual medicine. Rate ratios were calculated to compare the prevalence of use in 2010 and 2015. RESULTS: The study included 829,026 patients with a mean of 4.4 years of potential drug exposure. Overall prevalence of medicine use was 92% in 2010 and 93% in 2015. The mean number of prescriptions per patient-year for patients >=85 years of age (39.2) was almost double that of patients 65-74 years (21.8). Prevalence of use was similar between females (94%) and males (92%). Antibacterials, analgesics, cardiovascular drugs and proton pump inhibitors were the most widely used medicines. The use of systemic antibiotics increased by 2% between 2010 and 2015, but there were significant decreases in use of antithrombotics (6%), beta blockers (6%), diuretics (19%), nitrates (19%) and antiarrhythmics (24%). CONCLUSION: Our findings indicate both positive changes in response to guidance on safe and appropriate medicine use and several areas of concern. Continued monitoring of changing patterns in the medicine use of older people will be important, particularly with regard to the use of combinations of medicines that increase their risk of adverse events.

Understanding medicines with a propensity to increase the risk of heart failure: Combining existing knowledge with targeted population assessment.

PURPOSE: Existing knowledge of medicines that increase the risk of an adverse event may be corroborated and augmented by population studies specifically assessing the risk associated with the concurrent use of these medicines and use by patients with existing comorbidity. An American Heart Association review recently identified a variety of medicines that may cause or exacerbate heart failure (HF), many with evidence from limited evaluation of population data. We assessed the risk of first-time HF associated with the use of 50 of these medicines by New Zealand's primary care population. METHODS: Case-control study utilising national pharmaceutical use and hospital admissions data 2007-2015; 22,989 patients with first-time HF 2008-2015 were matched with 114 498 control patients. The primary outcome was first-time HF and its association with medicine exposure in the prior 90 days, estimated using conditional logistic regression. We also assessed the risk associated with new use of medicines in the prior month, concurrent use, and in patients with existing comorbidity. RESULTS: Eleven medicines were significantly associated with HF with several other infrequently used medicines providing signals of increased risk. A high risk was associated with the use of salbutamol (adjusted odds ratio 2.63; 95% CI, 2.48-2.78), clozapine (2.70; 2.46-4.98), diltiazem (1.52; 1.44-1.60), indomethacin (2.51; 1.54-4.10), pioglitazone (1.50; 1.16-1.95), and antifungal medicines. New use of medicines and use of medicine combinations increased this risk in many cases. CONCLUSIONS: Our study provides further evidence to inform cautious use of these medicines in patients with HF or at risk of developing HF.

Trends in Outpatient Prescription Medicine Use in New Zealand Children 2010-2015: A National Population-Based Study.

BACKGROUND: Research examining trends in the outpatient prescription medicine use of New Zealand children is limited. OBJECTIVES: Our objective was to provide an overview of prescription medicine use in New Zealand children and assess changing patterns in use from 2010 to 2015. METHODS: We conducted a retrospective cohort study including all New Zealand primary care-registered children aged < 18 years using data from the national pharmaceutical claims database. We calculated the prevalence of use within four age groups in each year by anatomical therapeutic class, therapeutic group and drug. Rate ratios were calculated to compare the prevalence of use in 2010 and 2015. RESULTS: In total, 1,496,026 children with a mean of 2.7 years of potential drug exposure were included. The overall prevalence of drug use was 70% in 2010 and 73% in 2015. In 2015, medicine use was highest in children aged < 2 years (90%) and lowest in children aged 12-17 years (65%). Antibacterials, analgesics, topical corticosteroids, non-steroidal anti-inflammatory drugs (NSAIDs) and antihistamines were the most widely used medicines. The prevalence of use of systemic and topical antibiotics decreased by 2 and 10%, respectively, between 2010 and 2015, but there was increased use of analgesics (10%), NSAIDs (39%), antihistamines (15%) and antinausea and vertigo agents (306%). CONCLUSIONS: Our findings indicate areas for further research focusing on inappropriate prescribing to children and safety issues in children's medicine use. Monitoring changing patterns of use over time is important for the evaluation of effective therapies in children and any potential harmful consequences of prescribing.

Atrial fibrillation in New Zealand primary care: Prevalence, risk factors for stroke and the management of thromboembolic risk.

Background Atrial fibrillation is a major risk factor for stroke and heart disease but there is limited information on its prevalence in New Zealand primary care or the treatment provided to manage thromboembolic risk. Our aim was to estimate the prevalence of atrial fibrillation, assess patient risk for thromboembolism and evaluate the appropriateness of risk reduction using antiplatelet and oral anticoagulation therapy. Design A retrospective cohort study utilising electronic medical records for 739,000 patients registered with 170 general practices in 2014. Methods Patient diagnoses and prescriptions from 2010-2014 were analysed to identify patients with atrial fibrillation in 2014 and co-morbidities included in the CHA2DS2-VASc algorithm. Adjusted prevalence of atrial fibrillation by patient demographic group and the proportion of patients following recommended antithrombotic therapy were calculated. Results 12,712 patients were identified with AF (1.72%, 95% confidence interval 1.69%-1.75%). Prevalence was significantly higher for Maori (odds ratio 1.91, 95% confidence interval 1.80-2.03) than Europeans after adjusting for age, sex, deprivation and clinical risk factors. Stroke risk for Maori and Pacific Island patients was higher than for Europeans across all age groups. Of the 10,406 patients (81.9%) at high risk for thromboembolism, 60.5% were using anticoagulants, 24.1% aspirin monotherapy and 15.4% neither anticoagulants nor aspirin. Oral anticoagulants were used by 31.5% of patients at low risk (CHA2DS2-VASc <2). Conclusions Oral anticoagulants are under-utilised in the management of thromboembolic risk in high risk patients with atrial fibrillation. Better promotion of guideline recommendations for the treatment of patients with atrial fibrillation may be required to improve clinician and patient decision-making.

Variation in the pharmaceutical costs of New Zealand general practices: a national database linkage study.

BACKGROUND: Variation in prescription costs between general practices and within practices over time is poorly understood. METHODS: From New Zealand's national health data collections, we extracted dispensed medicines data for 1045 general practices in 2011 and 917 practices continuously existing 2008-11. Using indirect standardization to account for patient demographics and morbidity, a standardized prescribing cost ratio (SPR: the ratio of actual : expected prescription costs) was calculated for each practice in each year. Case studies of three outlier clinics explored reasons for their status. RESULTS: SPRs ranged from 0.53 to 2.28 (median = 0.98). Of 469 practices with higher than expected costs (SPR > 1.0) in 2011, 204 (43.5%) had a single medicine or therapeutic drug class accounting for >15% of total costs. Case studies contrasted practices with overall pharmaceutical expenditure influenced strongly by a few patients needing high-cost medicines, more patients using medicines in one high-cost therapeutic drug class (antiretrovirals), and high medicine use across all therapeutic drug classes. CONCLUSIONS: Routine data collections can measure inter-practice variation in prescription costs, adjusted for differences in the demography and morbidity profile of each practice's patients. Small groups of patients using high-cost medicines influence general practices' expenditure on pharmaceuticals.

Risk factors for hospitalization due to diabetes complications.

AIM: To determine risk factors monitored in primary care that were significantly associated with diabetes complications requiring hospitalization. METHODS: We examined clinical and demographic data for 1080 Type 1 and 11,283 Type 2 New Zealand diabetes patients attending a free primary care diabetes examination between 2000 and 2002. Hospital admissions data for the 2 years following the index examination were linked for each patient using a unique National Health Index code. Logistic regression was used to determine odds ratios for the likelihood of developing diabetic complications adjusted for each variable. RESULTS: In the Type 1 cohort, 222 patients (20.6%) were hospitalized for diabetes complications and 1948 patients (17.3%) in the Type 2 cohort. In both cohorts, patients admitted with diabetes complications had significantly higher mean glycosylated haemoglobin (HbA1c) (p<0.001) and triglyceride levels (p<0.001), urine albumin:creatinine ratios (p<0.001) and duration of diabetes (p<0.01 Type 1: p<0.001 Type 2) than patients not admitted. In Type 2 patients, age, obesity, HbA1c, urine albumin:creatinine ratios, HDL levels and treatment with insulin or oral medication were all associated with increased odds of admission. CONCLUSIONS: Although it is well known that HbA1c is a significant predictor of diabetes complications, this study shows that urine albumin:creatinine ratio, body mass index, triglycerides and high density lipoproteins are also independent predictors of hospitalization for diabetes complications. Attention to all these factors in the primary care setting is indicated if the burden of diabetes complications to hospital services is to be minimized.