Considerations when planning and conducting large global observational studies: Experience from the DISCOVER study of patients with type 2 diabetes

DISCOVER is a global programme of observational research that includes patients with type 2 diabetes initiating second-line glucose-lowering therapy from 38 countries worldwide, including many with little or no previous epidemiological data available. More than 15,000 patients were followed-up for 3 years, and comprehensive data were collected using a standardized electronic case report form at enrolment, and 6, 12, 24 and 36 months. The study has formed the basis for a long-term registry that is intended to expand the geographic and clinical scope of the study and allow data collection beyond 3 years. In this review, critical aspects of study planning and implementation are summarized, along with challenges that were faced, to provide a resource for researchers planning similar studies. In particular, it is essential to set realistic expectations regarding the degree of study representativeness that can be achieved, allow for sufficient time to obtain ethics committee approval, develop tools to help recruit patients effectively, ensure that data collection systems are robust, user-friendly and adaptable, plan adequate remote and on-site monitoring, maximize patient retention through continuous engagement with study sites and ensure that everyone involved in the study forms a friendly and effective team. Observational studies such as DISCOVER are crucial for understanding disease epidemiology and management in real-world settings. They are also increasingly used by governmental, regulatory and payor agencies for post-marketing surveillance and when considering new drug submissions. The development of future studies of similar scope and ambition to DISCOVER is encouraged.

Benralizumab Prevents Recurrent Exacerbations in Patients with Chronic Obstructive Pulmonary Disease: A Post Hoc Analysis

Exacerbations in chronic obstructive pulmonary disease (COPD), which tend to occur in clusters and increase with disease severity, come with high societal and economic burdens. Prevention and delay of recurrent exacerbations is an unmet and significant therapeutic need for patients with COPD. GALATHEA (NCT02138916) and TERRANOVA (NCT02155660) were trials assessing efficacy of benralizumab in patients with frequent COPD exacerbations despite treatment. Although these studies found that benralizumab given as an add-on treatment did not significantly reduce annual rates of COPD exacerbations after 56 weeks of treatment, in the following exploratory post hoc analysis of the GALATHEA and TERRANOVA trials we identified a potential responder population in which treatment with benralizumab prevents recurrent COPD exacerbations during 30- and 90-day periods following an initial exacerbation, a vulnerable period for an exacerbation to occur. This responder population was characterized by high blood eosinophil counts and frequent previous exacerbations despite optimized triple therapy. These results highlight the importance of targeted therapies for high-risk populations and merit further research into the benefits of biologic therapies for COPD exacerbations.

Incidence rates and predictors of microvascular and macrovascular complications in patients with type 2 diabetes: Results from the longitudinal global discover study

BACKGROUND

Micro- and macrovascular complications are a major cause of morbidity and mortality in people with type 2 diabetes (T2D). We sought to understand the global incidence rates and predictors of these complications.

METHODS

We examined the incidence of vascular complications over 3 years of follow-up in the DISCOVER study-a global, observational study of people with T2D initiating second-line glucose-lowering therapy. Hierarchical Cox proportional hazards regression models examined factors associated with development of micro- and macrovascular complications during follow-up.

RESULTS

Among 11,357 people with T2D from 33 countries (mean age 56.9 ± 11.7 years, T2D duration 5.7 ± 5.1 years, HbA1c 8.4 ± 1.7%), 19.0% had a microvascular complication at enrolment (most commonly neuropathy), and 13.2% had a macrovascular complication (most commonly coronary disease). Over 3 years of follow-up, 16.0% developed an incident microvascular complication, and 6.6% had an incident macrovascular complication. At the end of 3 years of follow-up, 31.5% of patients had at least one microvascular complication, and 16.6% had at least one macrovascular complication. Higher HbA1c and smoking were associated with greater risk of both incident micro- and macrovascular complications. Known macrovascular complications at baseline was the strongest predictor for development of new microvascular complications (HR 1.40, 95% CI 1.21 -1.61) and new macrovascular complications (HR 3.39, 95% CI 2.84 -4.06).

CONCLUSIONS

In this global study, both the prevalence and 3-year incidence of vascular complications were high in patients with relatively short T2D duration, highlighting the need for early risk-factor modification.

Socioeconomic Factors Associated With Glycemic Measurement and Poor HbA1c Control in People With Type 2 Diabetes: The Global DISCOVER Study

DISCOVER is a 3-year observational study program of 15,983 people with type 2 diabetes initiating second-line glucose-lowering therapy in 38 countries. We investigated the association between socioeconomic status and both the availability of a baseline glycated hemoglobin (HbA1c) measurement and poor glycemic control (HbA1c level ≥ 9.0%) in participants enrolled in DISCOVER. Factors associated with a lack of baseline HbA1c measurement or an HbA1c level ≥ 9.0% were assessed using three-level hierarchical logistic models. Overall, 19.1% of participants did not have a baseline HbA1c measurement recorded. Lower-middle country income (vs. high) and primary/no formal education (vs. university education) were independently associated with a reduced likelihood of having a baseline HbA1c measurement (odds ratio [95% confidence interval]: 0.11 [0.03-0.49] and 0.81 [0.66-0.98], respectively. Of the participants with an available HbA1c measurement, 26.9% had an HbA1c level ≥ 9.0%; 68.7% of these individuals were from lower- or upper-middle-income countries. Factors associated with an increased likelihood of poor glycemic control included low country income, treatment at a site with public and/or governmental funding (vs. private funding) and having public or no health insurance (vs. private). A substantial proportion of DISCOVER participants did not have an HbA1c measurement; more than one-quarter of these participants had poorly controlled type 2 diabetes. Both individual- and country-level socioeconomic factors are associated with the quality of care regarding glycemic control. Awareness of these factors could help improve the management of patients with type 2 diabetes.

Early versus late intensification of glucose-lowering therapy in patients with type 2 diabetes: Results from the DISCOVER study

AIMS

To assess the effects of glycated haemoglobin (HbA_1c) levels at time of glucose-lowering treatment intensification in DISCOVER, a global observational study of patients with type 2 diabetes (T2D) initiating second-line therapy. Outcomes of interest were glycaemic control, hypoglycaemia, and need for further intensification during 3 years of follow-up.

METHODS

We included patients who intensified treatment (add-on or insulin initiation) upon initiation of second-line therapy (baseline). Outcomes were assessed according to baseline HbA_1c: HbA_1c ≤ 7·5% (early intensification) or HbA_1c > 7·5% (late intensification). Factors associated with early or late intensification were assessed using multivariate logistic regression.

RESULTS

Of the 9575 patients included, 3275 (34·2%) intensified treatment early and 6300 (65·8%) intensified treatment late. During follow-up, mean (SD) HbA_1c was lower in the early- than in the late-intensification group (6·9% [0·95%] vs 7·5% [1·28%] at 36 months). More patients had HbA_1c < 7·0% in the early- than in the late-intensification group (61·8% vs 37·9% at 36 months; p < 0·001). The risk of further intensification was higher in the late-intensification group (hazard ratio 1·88 [95% confidence interval 1·68-2·09]). Occurrence of hypoglycaemia was similar in both groups.

CONCLUSIONS

Late intensification of glucose-lowering therapy after first-line treatment failure reduces the likelihood of reaching recommended treatment goals.

Contemporary economic burden in a real-world heart failure population with Commercial and Medicare supplemental plans

BACKGROUND

Limited real-world data exist on healthcare resource utilization (HCRU) and associated costs of patients with heart failure (HF) with reduced ejection fraction (HFrEF) and preserved EF (HFpEF), including urgent HF visits, which are assumed to be less burdensome than HF hospitalizations (hHFs) HYPOTHESIS: This study aimed to quantify the economic burden of HFrEF and HFpEF, via a retrospective, longitudinal cohort study, using IBM® linked claims/electronic health records (Commercial and Medicare Supplemental data only).

METHODS

Adult patients, indexed on HF diagnosis (ICD-10-CM: I50.x) from July 2012 through June 2018, with 6-month minimum baseline period and varying follow-up, were classified as HFrEF (I50.2x) or HFpEF (I50.3x) according to last-observed EF-specific diagnosis. HCRU/costs were assessed during follow-up.

RESULTS

About 109 721 HF patients (22% HFrEF, 31% HFpEF, 47% unclassified EF; median 18 months' follow-up) were identified. There were 3.2 all-cause outpatient visits per patient-month (HFrEF, 3.3; HFpEF, 3.6); 69% of patients required inpatient stays (HFrEF, 80%; HFpEF, 78%). Overall, 11% of patients experienced hHFs (HFrEF, 23%; HFpEF, 16%), 9% experienced urgent HF visits (HFrEF, 15%; HFpEF, 12%); 26% were hospitalized less than 30 days after first urgent HF visit versus 11% after first hHF. Mean monthly total direct healthcare cost per patient was $9290 (HFrEF, $11 053; HFpEF, $7482).

CONCLUSIONS

HF-related HCRU is substantial among contemporary real-world HF patients in US Commercial or Medicare supplemental health plans. Patients managed in urgent HF settings were over twice as likely to be hospitalized within 30 days versus those initially hospitalized, suggesting urgent HF visits are important clinical events and quality improvement targets.

Dapagliflozin versus saxagliptin as add-on therapy in patients with type 2 diabetes inadequately controlled with metformin

OBJECTIVE

This analysis compared the efficacy and safety of the sodium-glucose cotransporter-2 (SGLT2) inhibitor, dapagliflozin, and the dipeptidyl peptidase-4 (DPP4) inhibitor, saxagliptin, both added on to metformin.

MATERIALS AND METHODS

This was a post-hoc analysis from a double-blind, randomized, 24-week clinical trial (NCT01606007) of patients with type 2 diabetes (T2D) inadequately controlled with metformin. We compared the dapagliflozin 10 mg (n = 179) and saxagliptin 5 mg (n = 176) treatment arms.

RESULTS

Dapagliflozin showed significantly greater mean reductions versus saxagliptin in HbA1c (difference versus saxagliptin [95% CI]: -0.32% [-0.54, -0.10]; p < 0.005), fasting plasma glucose (-0.98 [-1.42, -0.54] mmol/L; p < 0.0001), body weight (-2.39 [-3.08, -1.71] kg; p < 0.0001) and systolic blood pressure (SBP) (-3.89 [-6.15, -1.63] mmHg; p < 0.001). More dapagliflozintreated than saxagliptin-treated patients achieved the composite endpoint of HbA1c reduction ≥ 0.5%, weight loss ≥ 2 kg, SBP reduction ≥ 2 mmHg and no major/minor hypoglycemia (24% versus 7%). No major events of hypoglycemia were reported. More patients on dapagliflozin (6%) versus saxagliptin (0.6%) experienced genital infections.

CONCLUSION

Dapagliflozin demonstrated greater glycemic efficacy than saxagliptin with additional benefits on weight and SBP, and the safety profile was consistent with previous studies.

Seasonal variation in the serum 25-hydroxyvitamin D levels of young and elderly active and inactive adults in São Paulo, Brazil: The São PAulo Vitamin D Evaluation Study (SPADES)

OBJECTIVE

To evaluate the 25-hydroxyvitamin D [25(OH)D] concentrations in individuals in the city of São Paulo belonging to different age groups and exhibiting specific behavioral characteristics and to correlate the 25(OH)D concentration with the level of UV radiation (UVR).

PATIENTS AND METHODS

A total of 591 individuals were included, distributed as follows: 177 were living in institutions (NURSING, 76.2 ± 9.0 y old), 243 were part of the community elderly (COMMUNITY, 79.6 ± 5.3 y old), 99 were enrolled in a physical activity program targeting the elderly (ACTIVE, 67.6 ± 5.4 y old) and 72 were young (YOUNG, 23.9 ± 2.8 y old). Blood samples from all individuals were collected throughout the year. UVR measurements were taken by an official meteorology institution.

RESULTS

The UVR values varied throughout the year, following a sinusoidal-like pattern. Because of the Earth's orbit, we hypothesized that there would be cyclic patterns for the 25(OH)D and UVR values that repeat every 12 mo. The general formula is represented by the equation P1+P2⋅sin(-2⋅π12⋅(t-P3)) The mean 25(OH)D concentration and the amplitude of the variation were significantly higher for the YOUNG and ACTIVE groups than for the COMMUNITY and NURSING groups. The nadir for UVR was in June, whereas the nadir for the 25(OH)D concentration was in the spring, corresponding to a delay of one season.

CONCLUSIONS

There was seasonal variation in the 25(OH)D concentration for all the groups studied; however, the amplitude of the variation was higher for the groups of young and physically active people, possibly due to the higher level of sunlight exposure for these groups. The lowest 25(OH)D concentration was detected in the spring.

Factors affecting vitamin D status in different populations in the city of São Paulo, Brazil: the São PAulo vitamin D Evaluation Study (SPADES)

BACKGROUND

Hypovitaminosis D is a common condition among elderly individuals in temperate-climate countries, with a clear seasonal variation on 25 hydroxyvitamin D [(25(OH)D] levels, increasing after summer and decreasing after winter, but there are few data from sunny countries such as Brazil. We aimed to evaluate 25-hydroxyvitamin D concentrations and its determining factors, in individuals in the city of São Paulo belonging to different age groups and presenting different sun exposure habits.

METHODS

591 people were included as follows: 177 were living in institutions (NURSING HOMES, NH, 76.2 ± 9.0 years), 243 were individuals from the community (COMMUNITY DWELLINGS, CD, 79.6 ± 5.3 years), 99 were enrolled in physical activity program designed for the elderly (PHYSICAL ACTIVITY, PA, 67.6 ± 5.4 years) and 72 were young (YOUNG, 23.9 ± 2.8 years). Ionized calcium, PTH, 25(OH)D, creatinine and albumin were evaluated. ANOVA, Mann-Whitney and Kruskal Wallis tests, Pearson Linear Correlation and Multiple Regression were used in the statistical analysis.

RESULTS

25(OH)D mean values during winter for the different groups were 36.1 ± 21.2 nmol/L (NH), 44.1 ± 24.0 nmol/L (CD), 78.9 ± 30.9 nmol/L (PA) and 69.6 ± 26.2 nmol/L (YOUNG) (p < 0.001) while during summer they were 42.1 ± 25.9 nmol/L, 59.1 ± 29.6 nmol/L, 91.6 ± 31.7 nmol/L and 103.6 ± 29.3 nmol/L, respectively (p < 0.001). The equation which predicts PTH values based on 25(OH)D concentration is PTH = 10 + 104.24.e-(vitD-12.5)/62.36 and the 25(OH)D value above which correlation with PTH is lost is 75.0 nmol/L. In a multiple regression analysis having 25(OH)D concentration as the depending variable, the determining factors were PTH, ionized calcium and month of the year (p < 0.05).

CONCLUSIONS

Much lower 25(OH)D values were found for the older individuals when compared to younger individuals. This finding is possibly due to age and habit-related differences in sunlight exposure. The existence of seasonal effects on 25(OH)D concentration throughout the year was evident for all the groups studied, except for the nursing home group. According to our data, PTH values tend to plateau above 75 nmol/L.

Prevalência da deficiência, insuficiência de vitamina D e hiperparatiroidismo secundário em idosos institucionalizados e moradores na comunidade da cidade de São Paulo, Brasil

A ocorrência de fraturas osteoporóticas em idosos está relacionada às concentrações reduzidas de vitamina D e conseqüente hiperparatiroidismo secundário, sendo os institucionalizados de maior risco. No Brasil, por seu alto grau de insolação, infere-se que a quantidade de vitamina D da população seja adequada. Neste estudo, objetivamos avaliar as concentrações plasmáticas de 25-hidroxivitamina D (25OHD), paratormônio (PTH) e cálcio ionizado (Cai), assim como analisar a prevalência de hipovitaminose D e de hiperparatiroidismo secundário em idosos moradores da cidade de São Paulo. Estudamos 177 pacientes institucionalizados (125 mulheres e 52 homens) com idade média (DP) de 76,6 (9,0) anos, e 243 idosos ambulatoriais (168 mulheres e 75 homens) com 79,1 (5,9) anos. Nesta avaliação, 71,2% do grupo institucionalizado e 43,8% do ambulatorial possuíam valores de 25OHD menores do que o mínimo recomendado (50 nmol/l), sendo que as mulheres apresentaram valores consideravelmente mais baixos que os homens. O hiperparatiroidismo secundário ocorreu em 61,7% dos pacientes institucionalizados e em 54% dos ambulatoriais. Considerando os resultados obtidos, recomendamos a suplementação com doses eficientes de vitamina D para a população idosa brasileira, alem de sugerir uma discussão para a implementação de políticas de fortificação alimentar com vitamina D, especialmente direcionada àqueles com maior risco.

Influence of ultraviolet radiation on the production of 25 hydroxyvitamin D in the elderly population in the city of São Paulo (23 degrees 34'S), Brazil

The lack of vitamin D is a major changeable factor involved in the pathophysiology of osteoporosis. Since the major source for this hormone is its cutaneous synthesis via ultraviolet radiation (UVR), we studied the serum level of 25-hydroxyvitamin D (25OHD) in 250 free-living elderly people (79.1 years old) from a subtropical region according to the UVR incidence and its correlations with parathormone (PTH) and ionized calcium. UVR and 25OHD differed according to the season of the year (P<0.001), with greater radiation in the summer and less in the winter, whereas the 25OHD peak and nadir occurred in autumn and spring, respectively. The highest 25OHD mean was 67.2 nmol/l, and the lowest was 29.1 nmol/l corresponding, respectively, to the measure of the month subsequent to the one of most and least sunlight incidence. Clustered by season, the correlation between UVR and 25OHD for the following seasons was r=0.98 and between the PTH and 25OHD of corresponding seasons, r=-0.95. Vitamin D deficiency occurred in 15.4% of patients, insufficiency in 41.9% and secondary hyperparathyroidism in 55%. In conclusion, we found a seasonal variation in 25OHD levels that strongly correlated with the PTH levels when separated by the seasons of the year. The 25OHD levels correlated with the UVR of the previous quarter, requiring no less than 30 days for serum changes arising from exposure to or deprivation of UVR to be observed. The prevalence of vitamin D deficiency/insufficiency found was greater than expected, even when compared to countries exposed to less solar irradiation. Thus, measures to encourage greater sun exposure and food enrichment policies should also be considered.

Bone mineral density and osteoporosis among a predominantly Caucasian elderly population in the city of São Paulo, Brazil

This cross-sectional study covered 301 individuals over 70 years of age--207 women (W) and 94 men (M)--living in the city of São Paulo, Brazil. Our aims were to evaluate the prevalence of low bone mineral density (BMD) in this population and the possible factors that influence BMD. The subjects were submitted to a bone densitometry scan (DXA) to evaluate the BMD at lumbar spine (LS), femoral neck (FN), trochanter (T), total femur (TF) and total body composition. At the time, the participants filled in a questionnaire about lifestyle habits, diet and medical history, as well as having blood samples taken to check hormone and biochemical levels. Anthropometric parameters were measured. Osteopenia and osteoporosis were defined in accordance with the criteria suggested by the World Health Organization. In the different sites studied, the prevalence of osteopenia and osteoporosis varied, in men ranging 33.3-57.4% and 6.4-16.1%, respectively, and in women ranging 36.6-56.5% and 22.2-33.2%, respectively. Weight was the variable that most strongly correlated with BMD at the proximal femur in both sexes (men, r =0.44-0.52; women, r =0.48-0.52) and with BMD at LS in women (r =0.44). Height was the parameter that best correlated with BMD at LS in men (r =0.34). In men follicle-stimulating hormone, growth hormone and glycemia correlated with BMD at T and TF, while plasma albumin only correlated with BMD at T. In women glycemia correlated with BMD at LS, and follicle-stimulating hormone correlated with BMD at FN, T and TF. In conclusion, we found a high prevalence of osteopenia and osteoporosis in this population, with weight being the best predictor of BMD. The prevalence of osteoporosis and osteopenia at FN was as high in men as that observed in women.

Aerobic exercise capacity in normal adolescents and those with type 1 diabetes mellitus

OBJECTIVE

To compare the aerobic exercise capacity between normal adolescents and those with type 1 diabetes mellitus (T1DM).

METHODS

An experimental group with 72 individuals diagnosed with T1DM aged 9--20, time from diagnosis 4.9 +/- 3.6 yr, without clinical cardiopulmonary disease or anemia and a control group (C) with 46 healthy individuals aged 10--18, matched by age, weight, height, body mass index, and lean and fat mass (kg), underwent an incremental aerobic exercising test on a motorized treadmill, where gas exchange variables - peak pulmonary ventilation (VE), peak oxygen consumption (VO(2)), and carbon dioxide production (CO(2)) - as well as their heart rate (HR) and time to exhaustion were recorded.

RESULTS

Body mass composition had no significant difference between experimental and control groups, and male and female subjects had similar exercising performances. The mean of hemoglobin A1c in the control group was 5.2+/- 0.9% and in the diabetic group 8.1+/- 2.2%; p=0.000. The patients with T1DM showed lower levels of aerobic capacity than the control group. Their respective values for each variable were as follows: (i) maximal VO(2) (T1DM: 41.57+/-7.68 vs. C: 51.12+/- 9.94 mL/kg/min; p< 0.001) and (ii) maximal VE (T1DM: 76.39+/-19.93 vs. C: 96.90 +/- 25.72 mL/kg/min; p< 0.001). Patients with T1DM also had an earlier time to exhaustion (T1DM: 8.75+/-1.60 vs. 10.82+/-1.44 min).

CONCLUSIONS

Adolescent patients with T1DM showed a reduced aerobic exercising capacity when compared to healthy peers matched to anthropometric conditions. This potential condition should be taken into consideration by the time of evaluation of the aerobic performance of these patients with glycemic control level.

Marcadores Bioquímicos da Remodelação Óssea na Prática Clínica

Em situações fisiológicas os processos de reabsorção e formação ósseas são fenômenos acoplados e dependentes. O predomínio de um sobre o outro resulta em ganho ou perda de massa óssea. É esta capacidade de avaliação dinâmica que se deseja em um marcador de remodelação óssea. A osteocalcina sérica intacta e fosfatase alcalina óssea melhor representam o processo de formação óssea enquanto as piridinolinas e fragmentos telopeptídeos carboxi e amino-terminais do colágeno tipo I melhor refletem a reabsorção óssea. Na avaliação da resposta ao tratamento, marcadores de reabsorção têm grande sensibilidade e especificidade, sendo que a queda de seus valores após tratamento com anti-reabsortivos correlaciona-se com o ganho de massa óssea obtido. Os marcadores de remodelação, apesar de terem trazido grandes avanços no entendimento das doenças ósseas, ainda necessitam de melhor sensibilidade e especificidade para que sua larga utilização na clínica diária seja estimulada. Entretanto, podem auxiliar no diagnóstico e decisão terapêutica em casos difíceis e no acompanhamento do tratamento.