Using a pharmacoepidemiological approach to estimate diabetes type 2 prevalence in Portugal

Estimating Type 2 Diabetes Prevalence: A Model of Drug Consumption Data

Observational, cross-sectional prevalence studies are costly and time-consuming. The development of indirect methods estimating prevalence used to obtain faster, less-expensive, and more robust results would be an advantage for several healthcare applications. This study aimed to use the drug dispensing data from community pharmacies to estimate the prevalence of Type 2 Diabetes mellitus (T2DM) in the Portuguese population. A cross-sectional study was conducted using a database of dispensed medicines with an indication for Diabetes mellitus in 2018 and 2021, stratified by geographic region. The methodology was based on a sequential method of acquiring prevalence estimates obtained through exposure to medicines using the daily doses defined per thousand inhabitants per day and adjusted to the rate of adherence to therapy, prescription patterns, and concomitance of antidiabetic drugs. The estimated overall T2DM prevalence in 2018 was 13.9%, and it was 14.2% for 2021. The results show the increased consumption of antidiabetic drugs, with fixed-dose combination antidiabetics and new antidiabetics being particularly important in 2021. This work allowed for the development of a model to obtain the estimated prevalence of T2DM based on drug consumption, using a simple, fast, and robust method that is in line with the available evidence. However, with the recent expanding indications for new antidiabetics, the inclusion of further data in the model needs to be studied.

Recent trends in pirfenidone and nintedanib use for idiopathic pulmonary fibrosis in Australia

ObjectivesIdiopathic pulmonary fibrosis (IPF) is one of the most common forms of interstitial lung disease presenting in people aged ≥50 years. There is currently no cure for IPF, but two medications (pirfenidone and nintedanib) have been shown to slow the functional decline of the lungs. In 2017, these two medications were listed on the Pharmaceutical Benefits Scheme (PBS) for subsidisation in Australia. This study evaluated local trends in the use of these two medications.MethodsPrescription data for this analysis were obtained from the PBS Item Reports for the period May 2017-May 2020. Population data were extracted from the Australian Bureau of Statistics data cubes. A descriptive approach was used to conduct and report the analysis to illustrate trends in the use of these two medications and associated costs.ResultsThere were 44 010 prescriptions processed for the treatment for IPF in the 3-year period. Nintedanib use was higher than pirfenidone use, accounting for 54% of prescriptions. New South Wales accounted for 35% of the total prescriptions but, when standardised against population size, the Australian Capital Territory accounted for the highest proportion of prescriptions (24%). Prescriptions for nintedanib and pirfenidone were associated with a total cost of A$131 377 951 over the period 2017-20.ConclusionThis study provides initial information on prescription rates, practices and expenditure for pirfenidone and nintedanib. In addition, we provide some insight into possible pharmacological and epidemiological trends based on jurisdictional differences. Together, the results from this study provide a platform for future research given the dearth of information on IPF in Australia.What is known about the topic?Data regarding trends in the utilisation of antifibrotics for the treatment of IPF in Australia are currently limited.What does this paper add?This study demonstrated that nintedanib use was slightly higher than pirfenidone use, and that there were variations in jurisdictional prescribing practices. The highest number of prescriptions and costs were attributable to New South Wales but, when standardised against population size, the Australian Capital Territory had the highest number of prescriptions and costs.What are the implications for practitioners?This study provides some insights into the use of pirfenidone and nintedanib, as well as pharmacoepidemiological trends, in Australia, which is useful for economic evaluation and modelling future health expenditure.

Estimating the prevalence of diabetes mellitus and thyroid disorders using medication data in Flanders, Belgium

Background

Various methods exist to estimate disease prevalences. The aim of this study was to determine whether dispensed, self-reported and prescribed medication data could be used to estimate the prevalence of diabetes mellitus and thyroid disorders. Second, these pharmaco-epidemiological estimates were compared with prevalences based on self-reported diagnoses and doctor-registered diagnoses.

Methods

Data on medication for diabetes and thyroid disorders were obtained from three different sources in Flanders (Belgium) for 2008: a purely administrative database containing data on dispensed medication, the Belgian National Health Interview Survey for self-reported medication and diagnoses, and a patient record database for prescribed medication and doctor-registered diagnoses. Prevalences were estimated based on medication data and compared with each other. Cross-tabulations of dispensed medication and self-reported diagnoses, and prescribed medication and doctor-registered diagnoses, were investigated.

Results

Prevalences based on dispensed medication were the highest (4.39 and 2.98% for diabetes and thyroid disorders, respectively). The lowest prevalences were found using prescribed medication (2.39 and 1.72%, respectively). Cross-tabulating dispensed medication and self-reported diagnoses yielded a moderate to high sensitivity for diabetes (90.4%) and thyroid disorders (77.5%), while prescribed medication showed a low sensitivity for doctor-registered diagnoses (56.5 and 43.6%, respectively). The specificity remained above 99% in all cases.

Conclusions

This study was the first to perform cross-tabulations for disease prevalence estimates between different databases and within (sub)populations. Purely administrative database was shown to be a reliable source to estimate disease prevalence based on dispensed medication. Prevalence estimates based on prescribed or self-reported medication were shown to have important limitations.

A probabilistic bias analysis for misclassified categorical exposures, with application to oral anti-hyperglycaemic drugs

PURPOSE

The effect of drug exposure misclassification generally receives little attention in pharmacoepidemiological research. In this paper, we illustrate a probabilistic bias analysis approach for misclassified categorical exposures and apply it in a database study of oral anti-hyperglycaemic drugs (OADs).

METHODS

A cohort study based on the Health Search Database general-practice database was carried out by including 12 640 adult (≥40 years) patients newly treated with OADs during 2003-2010. The proportion of days covered by OADs prescriptions during the first year of follow-up was evaluated for each individual, either by means of the prescribed daily dose or the defined daily dose. The effect of misclassification on hypothetical OAD-outcome association profiles was assessed through the proposed probabilistic bias analysis approach, taking advantage of available exposure validation data.

RESULTS

During the first year of follow-up, the average (SD) number of months with OADs available was 7 (4) months and 5 (3) months according to the prescribed daily dose and defined daily dose metrics, respectively. Probabilistic bias analysis results based on validation data suggest that the effect of misclassification is complex, as conventional exposure-outcome association estimates may be of greater or lower magnitude than their misclassification-adjusted values.

CONCLUSIONS

Misclassification should be taken into account in database studies on the safety of prescribed medications. To this aim, investigators should take advantage of external exposure validation data in sensitivity analysis approaches such as ours. Copyright © 2016 John Wiley & Sons, Ltd.

Asthma/COPD drugs reflecting disease prevalence, patient adherence and persistence

The aim of this review is to discuss the methodological issues involved in using pharmacy-record databases of drug sales in pharmacoepidemiology and to illustrate the usefulness of such data in estimating disease prevalence, patient adherence and persistence to therapy. Recent studies show that asthma/chronic obstructive pulmonary disease (COPD) prevalence increases with age. The volume of acquired asthma/COPD drugs per patient also increases with age and was approximately 2.5-times higher for patients aged 60-69 years compared with patients aged 20-29 years. Despite this, there is a comparatively low interest in asthma/COPD research involving elderly individuals. Published asthma/COPD-prevalence data and drug-treatment-prevalence data correspond reasonably well. Short- as well as long-term studies on drug acquisition indicate that approximately a third of patients have drugs available to cover at least 80% of the prescribed treatment time. Only approximately a tenth of the patients acquired steroids or steroid combinations, corresponding to one daily defined dose per day over a 5-year treatment period. It is probable that asthma/COPD is undertreated in all age groups.

Pitfalls associated with the therapeutic reference pricing practice of asthma medication

Background

Therapeutic reference pricing (TRP) based on the WHO daily defined dose (DDD) is a method frequently employed for the cost-containment of pharmaceuticals. Our objective was to compare average drug use in the real world with DDD and to evaluate whether TRP based on DDD could result in cost savings on maintenance medication and the total direct health expenditures for asthma patients treated with Symbicort Turbuhaler (SYT) and Seretide Diskus (SED) in Hungary.

Methods

Real-world data were derived from the Hungarian National Health Insurance Fund database. Average doses and costs were compared between the high-dose and medium-dose SYT and SED groups. Multiple linear regressions were employed to adjust the data for differences in the gender and age distribution of patients.

Results

27,779 patients with asthma were included in the analysis. Average drug use was lower than DDD in all groups, 1.38-1.95 inhalations in both SED groups, 1.28-1.97 and 1.74-2.49 inhalations in the medium and high-dose SYT groups, respectively. Although the cost of SED based on the DDD would be much lower than the cost of SYT in the medium-dose groups, no difference was found in the actual cost of the maintenance therapy. No significant differences were found between the groups in terms of total medical costs.

Conclusions

Cost-containment initiatives by payers may influence clinical decisions. TRP for inhalation asthma drugs raises special concern, because of differences in the therapeutic profile of pharmaceuticals and the lack of proven financial benefits after exclusion of the effect of generic price erosion. Our findings indicate that the presented TRP approach of asthma medications based on the daily therapeutic costs according to the WHO DDD does not result in reduced public healthcare spending in Hungary. Further analysis is required to show whether TRP generates additional expenditures by inducing switching costs and reducing patient compliance. Potential confounding factors may limit the generalisability of our conclusions.

Discrepancies between prescribed and defined daily doses: a matter of patients or drug classes?

Purpose

Defined daily doses (DDD) are used for the measurement of drug utilisation. The aim of the study was to analyse whether differences between DDD and prescribed daily doses (PDD) exist for relevant drug classes such as antihypertensive drugs and, if so, whether they primarily depend on drug classes or patient-related factors.

Methods

Using the data of a large German statutory health insurance scheme, we analysed continuous prescriptions for the following antihypertensive drug classes: thiazide diuretics, beta-blockers, dihydropyridine calcium channel blockers (CCBs), angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-II receptor blockers (ARBs). We summed the doses of all dispensed drugs per person during a defined time frame. We calculated the PDD (= total dose divided by the number of days) and expressed them as the PDD:DDD ratio (= amount of DDD per day and person).

Results

During the study period, 149,704 patients continuously received an antihypertensive medication. The average PDD:DDD ratio ranged from 0.84 (beta-blockers) to 1.88 (ARBs) and 2.17 (ACEIs). The average prescribed dosage of each drug class remained unchanged, even if the patients had previously received another antihypertensive drug with another PDD:DDD ratio. For example, if patients were switched from a beta-blocker to an ACEI, the PDD:DDD ratio increased, on average, from 0.79 to 2.17. Vice versa, the ratio decreased for patients with a drug change from an ACEI to a beta-blocker from 2.06 to 0.75.

Conclusions

Even large differences between DDD and PDD seem to be a matter of drug classes and not primarily of patient characteristics.

Correlating pharmaceutical data with a national health survey as a proxy for estimating rural population health

BACKGROUND

Chronic disease accounts for nearly three-quarters of US deaths, yet prevalence rates are not consistently reported at the state level and are not available at the sub-state level. This makes it difficult to assess trends in prevalence and impossible to measure sub-state differences. Such county-level differences could inform and direct the delivery of health services to those with the greatest need.

METHODS

We used a database of prescription drugs filled in the US as a proxy for nationwide, county-level prevalence of three top causes of death: heart disease, stroke, and diabetes. We tested whether prescription data are statistically valid proxy measures for prevalence, using the correlation between prescriptions filled at the state level and comparable Behavioral Risk Factor Surveillance System (BRFSS) data. We further tested for statistically significant national geographic patterns.

RESULTS

Fourteen correlations were tested for years in which the BRFSS questions were asked (1999-2003), and all were statistically significant. The correlations at the state level ranged from a low of 0.41 (stroke, 1999) to a high of 0.73 (heart disease, 2003). We also mapped self-reported chronic illnesses along with prescription rates associated with those illnesses.

CONCLUSIONS

County prescription drug rates were shown to be valid measures of sub-state estimates of diagnosed prevalence and could be used to target health resources to counties in need. This methodology could be particularly helpful to rural areas whose prevalence rates cannot be estimated using national surveys. While there are no spatial statistically significant patterns nationally, there are significant variations within states that suggest unmet health needs.

Assistência ao diabetes no Sistema Único de Saúde: análise do modelo atual

O sistema de saúde nacional, impulsionado por contextos econômicos restritivos, passou por uma reestruturação organizacional na década de 1990, voltada à atenção primária. Apesar das reformas, a incidência de diabetes mellitus ainda atinge elevadas proporções. Devido à alta morbi-mortalidade, a prevenção dessa morbidade tem-se tornado foco atual, fazendo-se necessário o desenvolvimento de programas eficazes e viáveis ao Sistema Único de Saúde, tais como ênfase na prevenção primária, controle da incidência e complicações da doença. Para que isso ocorra, o modelo da atenção atual prestada ao paciente deve ser modificado, priorizando a atenção primária, com a substituição do modelo médico-hegemônico por uma equipe interdisciplinar, onde o farmacêutico, como membro da equipe, possa prover seus serviços, minimizando assim impactos sociais, humanísticos e econômicos que a doença acarreta para a sociedade. O objetivo da presente revisão foi abordar a temática do diabetes mellitus e as dificuldades do controle associado à ineficácia da logística adotada, principalmente no Sistema Único de Saúde.

Comparison of chronic analgesic drugs prevalence in Parkinson's disease, other chronic diseases and the general population

Patients with Parkinson's disease (PD) frequently experienced pain. Nevertheless, there are no epidemiological data about frequency of pain in PD. We compare pain prevalence using analgesic prescription in PD patients, in the general population and in two samples of painful patients: diabetics and osteoarthritis patients in France. Data were obtained from the French System of Health Insurance for the year 2005. Medications (antiparkinsonian, antidiabetics drugs and osteoarthritis drugs) were used for identification of PD, diabetic and osteoarthritis patients. We estimated the prevalence of analgesic drugs prescription (at least one analgesic drug) and the prevalence of chronic analgesic drugs prescription (more than 90 DDD of analgesic drug). The study included 11,466 PD patients. PD patients significantly received more prescription of analgesics than the general population (82% versus 77%,) and fewer than patients with osteoarthritis (82% versus 90%). No significant difference was found between PD and diabetic patients. The chronic prescription of analgesic drugs was more prevalent in PD patients (33%) than in the general population (20%) and in diabetic patients (26%) and similar to that in osteoarthritis patients. PD patients were more exposed than the general population and diabetics to opiates, acetaminophen, and adjuvant analgesics chronic use.

Dispensed volumes of anti-asthmatic drugs related to the prevalence of asthma and COPD in Sweden

PURPOSE

To explore the possibility of using dispensed volumes asthma/COPD drugs as a proxy for the combined prevalence of asthma plus COPD.

METHODS

The proportions of the Swedish population with inhalation drugs for asthma/COPD 2004 were obtained using three different databases. A pharmacy record database gave the volumes of dispensed drugs (defined daily doses, DDDs of R03A + R03B drugs) for each patient, 20 years and older. The X-plain database of Apoteket AB gave drug sales data for Sweden and Swedish population data were obtained from Swedish statistics.

RESULTS

The sales volumes of asthma/COPD drugs were much higher for older than for younger people. The volumes increased from 18 DDD/TID for the 20-29 year group up to 124 DDD/TID for patients 70-79 years, or about seven times. The average volumes per patient in the different age groups corresponded to one DDD/day in only three of the age groups (50-79 years). In the youngest group the average drug volume per patient corresponded to one DDD every second day, which may indicate undermedication. The percentages of the Swedish population with asthma/COPD drugs increased from 4.0% for 20-29 years old to 14.5% for 80+ years old, or 3.6 times. When head-to-head comparisons could be made between reported prevalence data of asthma and COPD and our data the two sets of data were in a reasonable agreement.

CONCLUSION

The prevalence of drug treatment, i.e. the proportion of the population with dispensed asthma/COPD drugs, could function as a proxy for the disease prevalence of asthma plus COPD.

Developments in post-marketing comparative effectiveness research

Physicians and insurers need to weigh the effectiveness of new drugs against existing therapeutics in routine care to make decisions about treatment and formularies. Because Food and Drug Administration (FDA) approval of most new drugs requires demonstrating efficacy and safety against placebo, there is limited interest by manufacturers in conducting such head-to-head trials. Comparative effectiveness research seeks to provide head-to-head comparisons of treatment outcomes in routine care. Health-care utilization databases record drug use and selected health outcomes for large populations in a timely way and reflect routine care, and therefore may be the preferred data source for comparative effectiveness research. Confounding caused by selective prescribing based on indication, severity, and prognosis threatens the validity of non-randomized database studies that often have limited details on clinical information. Several recent developments may bring the field closer to acceptable validity, including approaches that exploit the concepts of proxy variables using high-dimensional propensity scores, within-patient variation of drug exposure using crossover designs, and between-provider variation in prescribing preference using instrumental variable (IV) analyses.

Counting drugs to understand the disease: the case of measuring the diabetes epidemic

BACKGROUND

Diabetes prevalence increases globally with severe consequences for afflicted individuals and societies. Data on diabetes incidence and diabetes related mortality on a population level are, however, scarce. As an alternative to dedicated studies it has been suggested to use pharmacoepidemiological databases that are readily available, at least in the Nordic countries.

METHODS

For all 470,000 inhabitants in Funen County, Denmark, in the period 1992-2003, data on gender, date of birth, death and migration to and from the county, and any filled prescriptions of an anti-diabetic medication was obtained from the Odense Pharmaco-Epidemiological Database.

RESULTS

Prevalence odds for use of an anti-diabetic medication rose annually 3.5% (95% confidence interval: 3.1%, 3.9%) for females, 4.5% (4.0%, 4.9%) for males. Corresponding incidence rates annually rose 4.8% (3.8%, 5.8%) for females, 4.5% (3.5%, 5.4%) for males. Mortality rates among treated annually declined 2.8% (1.4%, 4.1%) among females, 2.2% (0.9%, 3.5%) among males. The disequilibrium in absolute numbers between incidence and mortality among treated was the main driver for the increasing prevalence, while concurrent trends in incidence and diabetes related mortality only marginally affected prevalence trends. Trend estimates were insensitive to varying the length of the run-in period used for determining treatment status, except when using the naive and methodologically flawed run-in period of variable length.

CONCLUSION

While pharmacoepidemiological databases provide a useful tool for monitoring pharmacologically treated diabetes, a dedicated diabetes database covering all prevalents and incidents is needed for a more detailed analysis of underlying causes and trends.