Results of observational studies: analysis of findings from the Nurses' Health Study

Paediatric visual impairment in Western Australia: Results and lessons from a registry analysis

AIM

Clinical registries are an important research tool to enhance our understanding of vision loss in the Australian paediatric population. We aim to provide an update on the epidemiology of visual impairment among Western Australian children using registry data analysis, and to highlight the challenges of registry data collection.

METHODS

This is a retrospective study of visual impairment and blindness registrations of children aged 0-16 years in Western Australia from 1996 to 2015. Blindness was defined as visual acuity ≤6/60 in the better-seeing eye or binocular visual field ≤20° diameter, with all other certifications labelled as visual impairment. Certificates were assessed for primary causes of vision loss by age strata and sex. Registration rate trends were analysed across three discrete registration periods.

RESULTS

Of 11 800 certificates issued between 1996 and 2015, 728 certificates (6.2%) were issued to 710 children. Five hundred and twenty-nine (74.5%) certificates were issued for visual impairment and 181 (25.5%) for blindness. The leading cause of certification was inherited retinal disease (73, 10.3%), followed by cortical visual impairment (57, 8.0%) and albinism (56, 7.9%). The annual registration rate of visual impairment increased from 0.5 to 9.8 per 100 000 person-years across the study period, whereas blindness rates fell from 2.7 to 1.3.

CONCLUSIONS

Overall registration rates of paediatric visual impairment in Western Australia are increasing, but these trends should be interpreted with caution given the known limitations of registry data. Enhancements of the registration process could be achieved through digitisation, inclusion of patient outcome data, and incentives for greater practitioner engagement.

Using data visualization to characterize whole-person health of public health nurses

OBJECTIVE

To characterize patterns in whole-person health of public health nurses (PHNs).

DESIGN AND SAMPLE

Survey of a convenience sample of PHNs (n = 132) in 2022. PHNs self-identified as female (96.2%), white (86.4%), between the ages 25-44 (54.5%) and 45-64 (40.2%), had bachelor's degrees (65.9%) and incomes of $50-75,000 (30.3%) and $75-100,000/year (29.5%).

MEASUREMENTS

Simplified Omaha System Terms (SOST) within the MyStrengths+MyHealth assessment of whole-person health (strengths, challenges, and needs) across Environmental, Psychosocial, Physiological, and Health-related Behaviors domains.

RESULTS

PHNs had more strengths than challenges; and more challenges than needs. Four patterns were discovered: (1) inverse relationship between strengths and challenges/needs; (2) Many strengths; (3) High needs in Income; (4) Fewest strengths in Sleeping, Emotions, Nutrition, and Exercise. PHNs with Income as a strength (n = 79) had more strengths (t = 5.570, p < .001); fewer challenges (t = -5.270, p < .001) and needs (t = -3.659, p < .001) compared to others (n = 53).

CONCLUSIONS

PHNs had many strengths compared to previous research with other samples, despite concerning patterns of challenges and needs. Most PHN whole-person health patterns aligned with previous literature. Further research is needed to validate and extend these findings toward improving PHN health.

Comparison of the outcomes of the prolonged antianginal therapy use in stable coronary artery disease patients according to the data of randomized and observational studies

Objective

To compare the results of treatment with antianginal drug nicorandil in patients with stable coronary artery disease according to the results of the observational study (OS) «NIKEA» and randomized controlled trial (RCT) «IONA».

Methods

«NIKEA » observational program included 590 patients with stable angina pectoris. Subgroups in the OS were formed based on the adherence to nicorandil use. Adherence was assessed during follow-up direct questioning. «IONA » RCT included 5126 patients with stable angina pectoris.

Results

Follow-up period and mean age of patients were equal in OS and RCT. In OS the group of adherent to nicorandil use patients had fewer males, life-saving drugs were administered significantly more often than in RCT, comorbidities (arterial hypertension, peripheral atherosclerosis and diabetes mellitus) were more pronounced. Angina pectoris class III was diagnosed in 32% of the OS patients vs 11% of the RCT patients, and class I – in 4.4% and 26%, respectively (р<0.001). Both in RCT and OS, there were significantly fewer cases of all cardiovascular events in the groups of nicorandil and adherent to nicorandil use patients in comparison with the groups of placebo and nonadherent patients. Both in RCT and OS the use of nicorandil led to significant decrease in the risk of all cardiovascular events.

Conclusion

Results of the efficacy and effectiveness studies complement each other and give the opportunity to assess the realisation of the RCT results in real clinical practice.

Factors Associated With Favorable Laser Trabeculoplasty Response: IRIS Registry Analysis

PURPOSE

We examined patients in a large clinical registry to assess factors associated with laser trabeculoplasty (LTP) responses.

DESIGN

Retrospective cohort study.

METHODS

StudyPopulation: LTP patients in the Intelligent Research in Sight (IRIS) Registry, 2013-2018.

OBSERVATION

IRIS Registry data were extracted if the eye had a procedural code for LTP and a glaucoma diagnosis. Eyes were excluded if LTP laterality or baseline intraocular pressure (IOP) could not be determined. Following LTP, "nonresponders" were those with <20% IOP reduction after 8 weeks, while "responders" were those with ≥20% IOP reduction. MainOutcomeMeasures: Proportion of responders, odds ratios (OR) of pre-LTP factors associated with being a nonresponder.

RESULTS

A total of 263,480 eyes were included, with mean age 71.4 ± 11.7 years. Mean baseline IOP was 19.1 ± 5.0 mm Hg, mean number of pre-LTP medications was 2.1 ± 1.5. Response rate was 36.9% overall and 68.8% for those with baseline IOP >24 mm Hg. Higher baseline IOP was associated with reduced odds of nonresponse (OR = 0.60, P < .0001 for a 3 mm Hg increase). Angle recession, uveitis, and aphakia increased the odds of a nonresponse (ORs 2.46, 1.50 (both P < .0001), and 1.55 (P = .0259), respectively). In nonresponders with at least 1 medication at baseline, 76.3% of eyes had fewer medications postoperatively.

CONCLUSIONS

Lower baseline IOP, angle recession, uveitis, and aphakia were associated with increased odds of nonresponse. Future studies that analyze LTP responder survival and implementation lag would facilitate resource optimization in glaucoma therapy.

Elevated Urate Levels Do Not Alter Bone Turnover Markers: Randomized Controlled Trial of Inosine Supplementation in Postmenopausal Women

OBJECTIVE

Observational studies have consistently demonstrated that serum urate level positively correlates with bone mineral density (BMD). We undertook this study to determine whether moderate hyperuricemia induced by inosine supplements influences bone turnover markers in postmenopausal women over a 6-month period.

METHODS

One hundred twenty postmenopausal women were recruited for a 6-month randomized, double-blind, placebo-controlled trial. Key exclusion criteria were osteoporosis, previous fragility fracture, bisphosphonate therapy, gout, kidney stones, and a urine pH level of ≤5.0. Participants were randomized in a 1:1 ratio to receive placebo or inosine. The coprimary end points were change in levels of N-propeptide of type I procollagen (PINP) and change in levels of β-C-telopeptide of type I collagen (β-CTX). Change in BMD, as measured by dual x-ray absorptiometry, was an exploratory end point.

RESULTS

Administration of inosine led to a significant increase in serum urate concentration over the study period (P < 0.0001 for all follow-up time points). At week 26, the mean change in serum urate concentration was +0.13 mmoles/liter (+2.2 mg/dl) in the inosine group and 0.00 mmoles/liter (0 mg/dl) in the placebo group. There was no difference in PINP or β-CTX levels between groups over the 6 months. There were no significant changes in bone density between groups over the 6 months. Adverse events and serious adverse events were similar between the 2 groups.

CONCLUSION

This clinical trial shows that although inosine supplementation leads to sustained increases in serum urate levels over a 6-month period, it does not alter markers of bone turnover in postmenopausal women. These findings do not support the concept that urate has direct biologic effects on bone turnover.

Big Health Data and Cardiovascular Diseases: A Challenge for Research, an Opportunity for Clinical Care

Cardiovascular disease (CVD) accounts for the majority of death and hospitalization, health care expenditures and loss of productivity in developed country. CVD research, thus, plays a key role for improving patients' outcomes as well as for the sustainability of health systems. The increasing costs and complexity of modern medicine along with the fragmentation in healthcare organizations interfere with improving quality care and represent a missed opportunity for research. The advancement in diagnosis, therapy and prognostic evaluation of patients with CVD, indeed, is frustrated by limited data access to selected small patient populations, not standardized nor computable definition of disease and lack of approved relevant patient-centered outcomes. These critical issues results in a deep mismatch between randomized controlled trials and real-world setting, heterogeneity in treatment response and wide inter-individual variation in prognosis. Big data approach combines millions of people's electronic health records (EHR) from different resources and provides a new methodology expanding data collection in three direction: high volume, wide variety and extreme acquisition speed. Large population studies based on EHR holds much promise due to low costs, diminished study participant burden, and reduced selection bias, thus offering an alternative to traditional ascertainment through biomedical screening and tracing processes. By merging and harmonizing large data sets, the researchers aspire to build algorithms that allow targeted and personalized CVD treatments. In current paper, we provide a critical review of big health data for cardiovascular research, focusing on the opportunities of this largely free data analytics and the challenges in its realization.

Clinical Registries in Ophthalmology

TOPIC

Clinical registries in ophthalmology.

CLINICAL RELEVANCE

In recent years, advancements in digital technology and increasing use of electronic medical records in health systems have led to the dramatic growth in large clinical data sets. Clinical data registries are organized systems that collect data on patients diagnosed with a disease or condition or who undergo a certain procedure.

METHODS

A search of the PUBMED database was conducted in January 2018 for clinical registries in ophthalmology.

RESULTS

Ninety-seven clinical eye registries were found, with significant growth in numbers in the last 4 decades. The most common conditions captured were blindness or low vision, corneal transplantation, glaucoma, and cataract surgery. Most registries originate in the European region, North America, and Australia. Nine registries had multinational coverage, whereas 48 were national registries. As the numbers and scope of clinical registries have expanded, valuable observational data have been used to study real-world clinical outcomes in healthcare quality measurement and improvement and to develop new guidelines and standards. Pertinent areas of its use include studying treatments and outcomes in cataract surgery, corneal transplantation, and macular degeneration.

CONCLUSIONS

The use of clinical registries for quality improvement and research has grown significantly in the last few decades, and this trend will continue as information technology infrastructures develop.

Assessment of research waste part 1: an exemplar from examining study design, surrogate and clinical endpoints in studies of calcium intake and vitamin D supplementation

BACKGROUND

Research waste is estimated to be very common, but assessments of its prevalence and scope are rare. As an example, we assessed research waste in clinical research on calcium intake (assessing study design and endpoint type) and vitamin D supplementation (assessing endpoint type).

METHODS

We examined 404 randomised controlled trials (RCTs) and observational studies of calcium intake (diet or supplements) and bone mineral density (BMD) or fracture, and 547 RCTs of vitamin D supplements, and assessed the proportion of studies that used surrogate or clinical endpoints. For studies with BMD or fracture as an endpoint, we estimated when the 'tipping' point occurred indicating the need for RCTs with fracture as an endpoint (based on cumulative meta-analyses of BMD RCTs, and chronological review of observational studies), and whether each study published at least 5y after the tipping point was novel, added new clinical knowledge or was research waste.

RESULTS

Observational studies of calcium intake and BMD or fracture outnumbered RCTs by 3.3-4.5 times. For both calcium intake and vitamin D supplements, studies using surrogate endpoints outnumbered studies using clinical endpoints by 1.6-3 times. Of 41 RCT publications of calcium intake and BMD or fracture published at least 5y after the tipping point in 1994, we considered that 19 (46%) lacked novelty, another 13 (32%) added no new clinical knowledge, and 30 (73%) were research waste. Of 204 observational study publications of calcium intake and BMD or fracture, 197 (96%) lacked novelty, another 5 (2%) added no new clinical knowledge, and 202 (99%) were research waste. Of 39 RCTs of vitamin D supplementation and BMD or fracture published at least 5y after the tipping point in 1999, 14 (36%) lacked novelty, another 13 (33%) added no new clinical knowledge, and 27 (69%) were research waste.

CONCLUSIONS

A high proportion of studies of calcium intake since 2000 (95%) and trials of vitamin D supplements since 2005 (69%) on BMD or fracture represent research waste.

Assessment of sugar-sweetened beverage consumption and weight change: a prospective cohort study

Background

In prospective studies, sugar-sweetened beverages (SSB) have been associated with weight increase. However, most prospective studies examine changes in body weight over time according to amounts of SSB intake at baseline, generally without considering changes over time in SSB, energy intake and physical activity. The objective of the present study was to examine how SSB intakes influence changes in weight, according to the way SSB intakes are analysed.

Methods

For a prospective cohort study with two nutritional assessments in time, 46 Flemish municipalities were selected by clustered random sampling. Within these municipalities, a random sample of men and women between 18 and 75 years of age was selected and invited to participate. In total, 562 middle-aged Belgian adults were tested in 2002 and 2012 for the same anthropometric, lifestyle, nutrition and physical activity parameters. The main outcome measured were weight changes from 2002 to 2012 were analysed according to various ways to parametrise SSB intakes in 2002 and changes in SSB, energy intake, and physical activity from 2002 to 2012.

Results

In a multivariable model including age, sex, the best predictors of weight changes were the weight at baseline (P < 0.001), then the change in energy intake (p = 0.068). No association was found with SSB intake at baseline (P = 0.267) and the change in SSB intake (P = 0.130).

Conclusions

Results of prospective studies on SSB intake and body weight depend much on the way SSB intakes are analysed, and on the inclusion of changes in energy intake and physical activity in analyses.

Medical big data: promise and challenges

The concept of big data, commonly characterized by volume, variety, velocity, and veracity, goes far beyond the data type and includes the aspects of data analysis, such as hypothesis-generating, rather than hypothesis-testing. Big data focuses on temporal stability of the association, rather than on causal relationship and underlying probability distribution assumptions are frequently not required. Medical big data as material to be analyzed has various features that are not only distinct from big data of other disciplines, but also distinct from traditional clinical epidemiology. Big data technology has many areas of application in healthcare, such as predictive modeling and clinical decision support, disease or safety surveillance, public health, and research. Big data analytics frequently exploits analytic methods developed in data mining, including classification, clustering, and regression. Medical big data analyses are complicated by many technical issues, such as missing values, curse of dimensionality, and bias control, and share the inherent limitations of observation study, namely the inability to test causality resulting from residual confounding and reverse causation. Recently, propensity score analysis and instrumental variable analysis have been introduced to overcome these limitations, and they have accomplished a great deal. Many challenges, such as the absence of evidence of practical benefits of big data, methodological issues including legal and ethical issues, and clinical integration and utility issues, must be overcome to realize the promise of medical big data as the fuel of a continuous learning healthcare system that will improve patient outcome and reduce waste in areas including nephrology.

Food science and food ingredients: the need for reliable scientific approaches and correct communication, Florence, 24 March 2015

This report summarises the proceedings of a conference organised by the Italian Association of Hospital Cardiologists. The aim was to consider the process by which dietary guidelines (DG) are developed and the quality of evidence underpinning these guidelines, as well as debating whether or not this has resulted in DG that are effective in terms of health improvement. Key points were a caution about false positives in research, the importance of holistic DG rather than single nutrient targets, the need for appropriate disease endpoints in studies and control of confounders, a plea for less reliance on observational studies which cannot address cause-and-effect relationships and a need to bear in mind unintended consequences. Options for improving the system and the quality of evidence were discussed.

Concordance of Results from Randomized and Observational Analyses within the Same Study: A Re-Analysis of the Women's Health Initiative Limited-Access Dataset

Background

Observational studies (OS) and randomized controlled trials (RCTs) often report discordant results. In the Women’s Health Initiative Calcium and Vitamin D (WHI CaD) RCT, women were randomly assigned to CaD or placebo, but were permitted to use personal calcium and vitamin D supplements, creating a unique opportunity to compare results from randomized and observational analyses within the same study.

Methods

WHI CaD was a 7-year RCT of 1g calcium/400IU vitamin D daily in 36,282 post-menopausal women. We assessed the effects of CaD on cardiovascular events, death, cancer and fracture in a randomized design- comparing CaD with placebo in 43% of women not using personal calcium or vitamin D supplements- and in a observational design- comparing women in the placebo group (44%) using personal calcium and vitamin D supplements with non-users. Incidence was assessed using Cox proportional hazards models, and results from the two study designs deemed concordant if the absolute difference in hazard ratios was ≤0.15. We also compared results from WHI CaD to those from the WHI Observational Study(WHI OS), which used similar methodology for analyses and recruited from the same population.

Results

In WHI CaD, for myocardial infarction and stroke, results of unadjusted and 6/8 covariate-controlled observational analyses (age-adjusted, multivariate-adjusted, propensity-adjusted, propensity-matched) were not concordant with the randomized design results. For death, hip and total fracture, colorectal and total cancer, unadjusted and covariate-controlled observational results were concordant with randomized results. For breast cancer, unadjusted and age-adjusted observational results were concordant with randomized results, but only 1/3 other covariate-controlled observational results were concordant with randomized results. Multivariate-adjusted results from WHI OS were concordant with randomized WHI CaD results for only 4/8 endpoints.

Conclusions

Results of randomized analyses in WHI CaD were concordant with observational analyses for 5/8 endpoints in WHI CaD and 4/8 endpoints in WHI OS.