Wing Cheuk Chan

Statin use in COPD patients is associated with a reduction in mortality: a national cohort study.

AIMS To assess whether statin use is associated with reduced mortality in patients with chronic obstructive pulmonary disease (COPD). METHODS Hospitalisation, drug dispensing, and mortality records were linked for New Zealanders aged 50-80 years discharged from hospital with a first admission with COPD in 2006. Patients were classified according to whether or not they were prescribed statins prior to admission. Baseline characteristics were compared and hazard ratios calculated for statin users versus statin non-users for all-cause mortality over follow-up of up to 4 years. RESULTS A total of 1,687 patients (mean age 70.6 years) were followed, including 596 statin users and 1,091 non-users. There were more men in the statin user group (58.4% vs. 48.5%), and statin users were more likely to have a history of cardiovascular disease (58.6% vs. 25.1%), prescription for frusemide as a proxy for heart failure (47.7% vs. 24.5%) or diabetes (35.4% vs.11.6%) than statin non-users (p<0.001). A total of 671 deaths occurred during the follow-up period. After adjustment for age, sex, ethnic group, history of cardiovascular disease, diabetes, and prescription for frusemide, the hazard ratio for statin users vs. statin non-users for all-cause mortality was 0.69 (95% CI 0.58 to 0.84). CONCLUSIONS Statin use is associated with a 30% reduction in all-cause mortality at 3-4 years after first admission for COPD, irrespective of a past history of cardiovascular disease and diabetes.

Explaining trends in coronary heart disease hospitalisations in New Zealand: trend for admissions and incidence can be in opposite directions

Background: A recent increase in the absolute number of hospitalisations for acute myocardial infarction (AMI) in New Zealand may signal a new epidemic of coronary heart disease (CHD). Objective: To quantify the impact of factors other than incidence of disease on these national hospitalisation trends. Methods: A total of 324 663 electronic records of New Zealand public CHD hospitalisations from 1993 to 2005 were examined. Repeat admissions were identified by record linkage using a unique national health identifier for each patient. Results: Hospitalisations for AMI increased by about 8% a year throughout the 13-year study period. Interhospital transfers increased by 117% over the study period, while readmissions increased by 42%. By 2005 over 60% of all admissions for CHD were readmissions. After accounting for readmissions, hospital transfers and population changes, the age-standardised first AMI hospitalisation rate peaked in 1995 and has since declined by 15%. Reciprocal trends in AMI and angina hospitalisations were seen, indicating changing diagnostic criteria. Overall hospitalisation rates for first CHD events remained relatively steady at about 216.4 events per 100 000 between 1993 and 2000 and subsequently declined by 25% to 162.2 events per 100 000 in 2005. Conclusion: Recent trends in hospitalisation rates for AMI are significantly influenced by factors other than underlying changes in CHD incidence. Increasing absolute numbers of admissions coded as AMI in New Zealand between 1993 and 2005 can be accounted for by increases in readmissions, increases in interhospital transfers, changes in diagnostic criteria for AMI and in demography.

Initiation and maintenance of cardiovascular medications following cardiovascular risk assessment in a large primary care cohort: PREDICT CVD-16.

Aim: To examine whether use of a standardized cardiovascular disease (CVD) risk assessment recommended by national guidelines is associated with appropriate initiation and maintenance of medication in a large primary care cohort. Methods and design: A total of 90,631 people aged 30−80 years were followed for up to 3 years after a formal CVD risk assessment was undertaken between January 2006 and October 2009, during routine primary care visits in New Zealand. Patients either had prior CVD or had their CVD risk estimated using a modified Framingham prediction equation for fatal or non-fatal CVD events. The individual risk profiles were anonymously linked to national dispensing data for blood-pressure-lowering and lipid-lowering medications in the 6-month period before and in consecutive 6-month blocks after the baseline CVD risk assessment. Results: At baseline, a combination of blood-pressure-lowering and lipid-lowering therapy was already being used by about two-thirds of patients with prior CVD, one-quarter with a 5-year CVD risk greater than 10% (approximately 20% 10-year risk), and one-tenth with CVD risk below this level. Among these previously treated patients, dispensing rates for blood-pressure-lowering, lipid-lowering, or both medications together declined by only 4⊟16% up to 3 years after baseline assessment, irrespective of risk category. Among patients untreated at baseline, combination therapy was initiated within 6 months for 21% with prior CVD, 16% with 5-year CVD risk greater than 15% (approximately 30% 10-year risk and the national drug-treatment threshold), 10% with 5-year CVD risk between 10 and 14% (approximately 20⊟29% 10-year risk), and 3% in the lowest risk category. Across the study population, patients with prior CVD had the highest dispensing rates for each category of medication, and incrementally higher dispensing rates were noted as CVD risk group increased. Conclusions: In this primary care cohort, most patients already using CVD medications at the time of the baseline CVD risk assessment maintained treatment over a maximum of 3 years follow up, irrespective of their estimated baseline risk. Among patients untreated at baseline, subsequent dispensing rates were strongly related to estimated CVD risk group. Around 15⊟20% of untreated patients meeting national drug-treatment criteria commenced combination pharmacotherapy within 6 months of CVD risk assessment.

Four out of ten patients are not taking statins regularly during the 12 months after an acute coronary event.

Background: In New Zealand, a setting in which national guidelines recommend statins for all patients with coronary heart disease (CHD) and cost barriers are low, patterns of use of these drugs are unknown. We investigated dispensing rates after hospital discharge for acute CHD event. Design: Retrospective cohort study. Methods: Drug dispensing, hospital diagnosis, and mortality records were linked by unique identifier for all New Zealanders aged 35–84 years after discharge following acute CHD event in 2007. We defined the statin dispensing ratio (SDR) as the proportion of days that 15,506 patients aged 35–84 years were dispensed such agents during the 12 months post discharge. An SDR ≥0.8 (80% or more days covered) was considered optimal. Results: Overall, 59% of the cohort had an SDR ≥0.8. Of patients dispensed statins in the 3 months before admission (n = 5506), almost all (99%; 5466) continued treatment during follow up and 82% had an SDR ≥0.8. In contrast, for patients not dispensed statins before admission (n = 8014), only two–thirds started statins during follow up and only 44% had an SDR ≥0.8. Of all patients with low statin dispensing (SDR <0.8), about one–quarter were not dispensed any lipid-lowering drugs, one-quarter received alternative lipid-lowering drugs, one-quarter stopped statins, and the remaining quarter were intermittent statin users. Conclusion: In a setting with few barriers to statin treatment, about 40% of patients had suboptimal statin dispensing during the year after hospital treatment for CHD. This study has identified four significant categories of suboptimal adherence that could inform quality improvement programmes.

Can the incidence and prevalence of coronary heart disease be determined from routinely collected national data? Population-based estimates for New Zealand in 2001--03.

Objective: To produce internally consistent estimates of coronary heart disease (CHD) incidence, prevalence, survival and mortality as a decision aid for service planning and resource allocation.

First and recurrent ischaemic heart disease events continue to decline in New Zealand, 2005–2015

Objectives To examine recent trends in first and recurrent ischaemic heart disease (IHD) deaths and hospitalisations. Methods Using anonymous patient-linkage of routinely collected data, all New Zealanders aged 35–84 years who experienced an International Statistical Classification of Diseases and Related Health Problems I(CD)-coded IHD hospitalisation and/or IHD death between 1 January 2005 and 31 December 2015 were identified. A 10-year look-back period was used to differentiate those experiencing first from recurrent events. Age-standardised hospitalisation and mortality rates were calculated for each calendar year and trends compared by sex and age. Results 160 109 people experienced at least one IHD event (259 678 hospitalisations and 35 548 deaths) over the 11-year study period, and there was a steady decline in numbers (from almost 24 000 in 2005 to just over 16 000 in 2015) and in age-standardised rates each year. With the exception of deaths in younger (35–64 years) women with prior IHD, there was a significant decline in IHD events in men and women of all ages, with and without a history of IHD. The decline in IHD mortality was greater for those experiencing a first rather than recurrent IHD event (3.8%–5.2% vs 0%–3.7% annually on average). In contrast, the decline in IHD hospitalisations was greater for those experiencing a recurrent compared with a first IHD event (5.6%–7.3% vs 3.2%–5.7% annually on average). Conclusions The substantial decline in IHD hospitalisations and mortality observed in New Zealanders with and without prior IHD between 2005 and 2015 suggests that primary and secondary prevention efforts have been effective in reducing the occurrence of IHD events.

The future of population registers: linking routine health datasets to assess a population's current glycaemic status for quality improvement

Objectives To determine the diabetes screening levels and known glycaemic status of all individuals by age, gender and ethnicity within a defined geographic location in a timely and consistent way to potentially facilitate systematic disease prevention and management. Design Retrospective observational study. Setting Auckland region of New Zealand. Participants 1 475 347 people who had utilised publicly funded health service in New Zealand and domicile in the Auckland region of New Zealand in 2010. The health service utilisation population was individually linked to a comprehensive regional laboratory repository dating back to 2004. Outcome measures The two outcomes measures were glycaemia-related blood testing coverage (glycated haemoglobin (HbA1c), fasting and random glucose and glucose tolerance tests), and the proportions and number of people with known dysglycaemia in 2010 using modified American Diabetes Association (ADA) and WHO criteria. Results Within the health service utilisation population, 792 560 people had had at least one glucose or HbA1c blood test in the previous 5.5 years. Overall, 81% of males (n=198 086) and 87% of females (n=128 982) in the recommended age groups for diabetes screening had a blood test to assess their glycaemic status. The estimated age-standardised prevalence of dysglycaemia was highest in people of Pacific Island ethnicity at 11.4% (95% CI 11.2% to 11.5%) for males and 11.6% (11.4% to 11.8%) for females, followed closely by people of Indian ethnicity at 10.8% (10.6% to 11.1%) and 9.3% (9.1% to 9.6%), respectively. Among the indigenous Maori population, the prevalence was 8.2% (7.9% to 8.4%) and 7% (6.8% to 7.2%), while for ‘Others’ (mainly Europeans) it was 3% (3% to 3.1%) and 2.2% (2.1% to 2.2%), respectively. Conclusions We have demonstrated that the data linkage between a laboratory repository and national administrative datasets has the potential to provide a systematic and consistent individual level clinical information that is relevant to medical auditing for a large geographically defined population.

The burden of coronary heart disease in Māori: population-based estimates for 2000-02

Objective: To estimate coronary heart disease (CHD) incidence, prevalence, survival, case fatality and mortality for Māori, in order to support service planning and resource allocation.

Can administrative health utilisation data provide an accurate diabetes prevalence estimate for a geographical region

AIM To validate the New Zealand Ministry of Health (MoH) Virtual Diabetes Register (VDR) using longitudinal laboratory results and to develop an improved algorithm for estimating diabetes prevalence at a population level. METHODS The assigned diabetes status of individuals based on the 2014 version of the MoH VDR is compared to the diabetes status based on the laboratory results stored in the Auckland regional laboratory result repository (TestSafe) using the New Zealand diabetes diagnostic criteria. The existing VDR algorithm is refined by reviewing the sensitivity and positive predictive value of the each of the VDR algorithm rules individually and as a combination. RESULTS The diabetes prevalence estimate based on the original 2014 MoH VDR was 17% higher (n = 108,505) than the corresponding TestSafe prevalence estimate (n = 92,707). Compared to the diabetes prevalence based on TestSafe, the original VDR has a sensitivity of 89%, specificity of 96%, positive predictive value of 76% and negative predictive value of 98%. The modified VDR algorithm has improved the positive predictive value by 6.1% and the specificity by 1.4% with modest reductions in sensitivity of 2.2% and negative predictive value of 0.3%. At an aggregated level the overall diabetes prevalence estimated by the modified VDR is 5.7% higher than the corresponding estimate based on TestSafe. CONCLUSION The Ministry of Health Virtual Diabetes Register algorithm has been refined to provide a more accurate diabetes prevalence estimate at a population level. The comparison highlights the potential value of a national population long term condition register constructed from both laboratory results and administrative data.