Measuring clinician experience in value-based healthcare initiatives: a 10-item core clinician experience measure (CEM-10)

Objective Clinician's experiences of providing care are identified as a key outcome associated with value-based healthcare (VBHC). In contrast to patient-reported experience measures, measurement tools to capture clinician's experiences in relation to VBHC initiatives have received limited attention to date. Progressing from an initial 18-item clinician experience measure (CEM), we sought to develop and evaluate the reliability of a set of 10 core clinician experience measure items in the CEM-10. Methods A multi-method project was conducted using a consensus workshop with clinicians from a range of NSW Health local health districts to reduce the 18-item CEM to a short form 10-item core clinician experience measure (CEM-10). The CEM-10 was deployed with clinicians providing diabetes care, care for older adults and virtual care across all districts and care settings of New South Wales, Australia. Psychometric analysis was used to determine the internal consistency of the tool and its suitability for diverse clinical contexts. Results Consensus building sessions led to a rationalised 10-item tool, retaining the four domains of psychological safety (two items), quality of care (three items), clinician engagement (three items) and interprofessional collaboration (two items). Data from four clinician cohorts (n  = 1029) demonstrated that the CEM-10 four-factor model produced a good fit to the data and high levels of reliability, with factor loadings ranging from 0.77 to 0.92, with Cronbach's alpha (range: 0.79-0.90) and composite reliability (range: 0.80-0.92). Conclusions The CEM-10 provides a core set of common clinician experience measurement items that can be used to compare clinician's experiences of providing care between and within cohorts. The CEM-10 may be supported by additional items relevant to particular initiatives when evaluating VBHC outcomes.

Qualitative and Quantitative Evaluation of an Innovative Primary and Secondary Diabetes Clinic in Western Sydney

Introduction

Western Sydney Diabetes (WSD) established an innovative diabetes service in May 2020, using virtual and in-person care, linking primary care with the diabetes specialist team. This study evaluated the service's feasibility using qualitative and quantitative methods.

Method

Evaluation included: 1) thematic analysis of interviews and workshops with patients and health professionals (n = 28); 2) quantitative analysis of records of patients admitted July 2020-June 2021 (n = 110).

Results

Key themes related to 1) benefits: convenient location, access to integrated care, advantages of virtual care; 2) challenges: hard for patients to ask questions, technology issues; 3) confidence: shared care decision making, multidisciplinary team; and 4) future directions: additional multidisciplinary services, expanded insulin stabilisation service, promotion.Improvements between baseline and 3 months included 1.3% reduction in HbA1c (p < 0.05). Sulfonylurea dropped by 25% between initial appointment and follow-up, and GLP1RA/SGLT2i use increasing by 30% (p < 0.05). The clinic covered costs using Medicare billings and Nationally Weighted Activity Units.

Discussion

The findings suggest this integrated care model was feasible and perceived as beneficial by both patients and providers. The clinic offers a promising model of practice that could be developed further to roll out in other regions for rural delivery of care.

Diabetic Retinopathy Screening at the Point of Care (DR SPOC): detecting undiagnosed and vision-threatening retinopathy by integrating portable technologies within existing services

INTRODUCTION

The aim of this study was to determine the prevalence of diabetic retinopathy (DR) in a low socioeconomic region of a high-income country, as well as determine the diagnostic utility of point-of-care screening for high-risk populations in tertiary care settings.

RESEARCH DESIGN AND METHODS

This was a cross-sectional study of patients with diabetes attending foot ulcer or integrated care diabetes clinics at two Western Sydney hospitals (n=273). DR was assessed using portable, two-field, non-mydriatic fundus photography and combined electroretinogram/ pupillometry (ERG). With mydriatic photographs used as the reference standard, sensitivity and specificity of the devices were determined. Prevalence of DR and vision-threatening diabetic retinopathy (VTDR) were reported, with multivariate logistic regression used to identify predictors of DR.

RESULTS

Among 273 patients, 39.6% had any DR, while 15.8% had VTDR, of whom 59.3% and 62.8% were previously undiagnosed, respectively. Non-mydriatic photography demonstrated 20.2% sensitivity and 99.5% specificity for any DR, with a 56.7% screening failure rate. Meanwhile, mydriatic photography produced high-quality images with a 7.6% failure rate. ERG demonstrated 72.5% sensitivity and 70.1% specificity, with a 15.0% failure rate. The RETeval ERG was noted to have an optimal DR cut-off score at 22. Multivariate logistic regression identified an eGFR of ≤29 mL/min/1.73 m2, HbA1c of ≥7.0%, pupil size of <4 mm diameter, diabetes duration of 5-24 years and RETeval score of ≥22 as strong predictors of DR.

CONCLUSION

There is a high prevalence of vision-threatening and undiagnosed DR among patients attending high-risk tertiary clinics in Western Sydney. Point-of-care DR screening using portable, mydriatic photography demonstrates potential as a model of care which is easily accessible, targeted for high-risk populations and substantially enhances DR detection.

Evaluating the Effectiveness of Joint Specialist Case Conferences in Improving Diabetes Control in Patients With Schizophrenia on Clozapine

ABSTRACT

Clozapine treatment for schizophrenia is typically long-term and is associated with a high rate of diabetes. Mental health and diabetes specialist teams at a local hospital in Australia have undertaken a series of joint specialist case conferences (JSCCs) where the diabetes team works with the psychiatry team to improve diabetes management. In this retrospective cohort study conducted between 2013 and 2018, we found that glycemic control in clozapine clinics linked with JSCCs was improved significantly compared with that in the non-JSCC clinics. In the non-JSCC clozapine clinics (control), the poor glycemic control rates stayed at a similar level: 23% in 2013 and 24% in 2018. In contrast, whereas the control patients' poor glycemic rate in JSCC clozapine clinics in 2013 was 24%, it decreased markedly in 2018 to 13%. This study indicates that JSCCs can improve diabetes outcomes in a group of patients with severe mental illness.

Diabetes during the COVID-19 pandemic: are people getting access to the right level of care?

INTRODUCTION

Avoidance of health services, in particular hospital and community services, is problematic for people with diabetes. Evidence has demonstrated that such missed attendances are associated with worse health, faster declines in functioning, and higher rates of mortality long-term. This paper investigated the impact of the pandemic on healthcare access across community and hospital care, including Virtual Care (VC) using several large datasets of General Practice (GP) and hospital services in western Sydney.

METHODS

A retrospective cohort study using a time-series database of 173,805 HbA_1c tests done at Blacktown and Mt Druitt hospitals and 1.8 million recorded consultations at GP clinics in the region was undertaken.

RESULTS

The average rate of diabetes in Emergency Department fell from 17.8% pre-pandemic to 11% after January 2020 (p < 0.001). This rate varied substantially over time, and correlated well with large outbreaks of COVID-19 in the state. Conversely, attendances of people with diabetes to GP clinics, especially using VC services, increased substantially over the pandemic period.

DISCUSSION/CONCLUSION

During the pandemic there was a substantial avoidance of hospital care by patients with diabetes. However, this may have been replaced by VC offered in the community for those with less severe diseases.

Evaluating clinician experience in value-based health care: the development and validation of the Clinician Experience Measure (CEM)

BACKGROUND

Clinicians' experiences of providing care constitute an important outcome for evaluating care from a value-based healthcare perspective. Yet no currently available instruments have been designed and validated for assessing clinicians' experiences. This research sought to address this important gap by developing and validating a novel instrument in a public health system in Australia.

METHODS

A multi-method project was conducted using co-design with 12 clinician leaders from a range of NSW Health Local Health Districts to develop the Clinician Experience Measure (CEM). Validity and reliability analyses were conducted in two stages, first assessing face and content validity with a pool of 25 clinicians and then using psychometric analysis with data from 433 clinicians, including nurses, doctors and allied health and representing all districts within one jurisdiction in Australia.

RESULTS

Data gathered from 25 clinicians via the face and content validity process indicated that the initial 31-items were relevant to the range of staff employed in the NSW state health system, with minor edits made to the survey layout and wording within two items. Psychometric analysis led to a rationalised 18-item final instrument, comprising four domains: psychological safety (4-items); quality of care (5-items); clinician engagement (4-items) and interprofessional collaboration (5-items). The 18-item four-factor model produced a good fit to the data and high levels of reliability, with factor loadings ranging from .62 to .94, with Cronbach's alpha (range: .83 to .96) and composite reliability (range: .85 to .97).

CONCLUSIONS

The CEM is an instrument to capture clinicians' experiences of providing care across a health system. The CEM provides a useful tool for healthcare leaders and policy makers to benchmark and assess the impact of value-based care initiatives and direct change efforts.

Type 2 diabetes self-management schemas across diverse health literacy levels: a qualitative investigation

OBJECTIVE

The aim of this study was to explore how people with diabetes and diverse health literacy levels conceptualise their experience and efforts to engage in self-management behaviours (their self-management 'schemas').

DESIGN

A qualitative design was applied.

METHODS

Twenty-six people in Sydney, Australia, took part in semi-structured interviews, which were audio-recorded and coded using Framework analysis.

RESULTS

Half the participants (54%) had limited health literacy, whereas 38% adequate health literacy (using Newest Vital Sign). Regardless of health literacy, people described how monitoring increased self-management awareness and signalled periods of low self-management ('lulls'). Accounts of monitoring to sustain motivation were more apparent for participants with adequate health literacy. Most participants described simple and flexible rules (e.g. use artificial sweeteners; eat in moderation). Two schemas related to 'lulls': a 'problem-solving orientation' depicted lulls as inevitable and was associated with varied coping strategies; a 'willpower orientation' attributed lulls to lack of 'willpower,' and described willpower as a main coping strategy.

CONCLUSION

There is considerable variation in how people think about their diabetes self-management and the strategies they use. Health literacy may contribute to some of this variation. Self-management interventions could benefit from depicting motivation as fluctuating and challenging ideas about willpower and self-blame.

Evaluating the cost and wait-times of a task-sharing model of care for diabetic eye care: a case study from Australia

OBJECTIVES

To determine whether a collaborative model of care that uses task-sharing for the management of low-risk diabetic retinopathy, Community Eye Care (C-EYE-C), can improve access to care and better use resources, compared with hospital-based care.

DESIGN

Retrospective audit of medical and financial records to compare two models of care.

SETTING

A large, urban tertiary Australian publicly funded hospital.

INTERVENTION

C-EYE-C is a collaborative care model, involving community-based optometrist assessment and 'virtual review' by ophthalmologists to manage low-risk patients. The C-EYE-C model of care was implemented from January to October 2017.

PARTICIPANTS

New low-risk patient referrals with diabetes received at a tertiary hospital ophthalmology unit.

PRIMARY AND SECONDARY OUTCOMES

Historical standard hospital care was compared with C-EYE-C for attendance, wait-times, outcomes and costs. Clinical concordance between the optometrist and ophthalmologist diagnosis and management was assessed using weighted kappa statistic.

RESULTS

There were 133 new low-risk referrals, managed in standard hospital care (n=68) and C-EYE-C (n=65). Attendance rates were similar between the models of care (72.1% hospital vs 67.7% C-EYE-C, p=0.71). C-EYE-C had shorter appointment wait-time (53 vs 118 days, p<0.01). In the C-EYE-C model of care, 68.2% of patients did not require hospital appointments and costs were 43% less than hospital care. There was substantial agreement between optometrists and ophthalmologists for diagnosis (κ=0.64, CI 0.47-0.81) and management (κ=0.66, CI 0.45-0.87).

CONCLUSION

This Australian study showed that collaborative eye care resulted in reduced patient waiting times and considerable cost-savings, while maintaining a high standard of patient care compared with traditional hospital-based care in the management of low-risk hospital referrals with diabetic eye disease. The improved access and reduced costs were largely the result of better task allocation through greater utilisation of primary eye care professionals to provide services for low-risk patients. Better resource use may free up further resources for other eye care services.

Rates of Attrition and Dropout in App-Based Interventions for Chronic Disease: Systematic Review and Meta-Analysis

Background

Chronic disease represents a large and growing burden to the health care system worldwide. One method of managing this burden is the use of app-based interventions; however attrition, defined as lack of patient use of the intervention, is an issue for these interventions. While many apps have been developed, there is some evidence that they have significant issues with sustained use, with up to 98% of people only using the app for a short time before dropping out and/or dropping use down to the point where the app is no longer effective at helping to manage disease.

Objective

Our objectives are to systematically appraise and perform a meta-analysis on dropout rates in apps for chronic disease and to qualitatively synthesize possible reasons for these dropout rates that could be addressed in future interventions.

Methods

MEDLINE (Medical Literature Analysis and Retrieval System Online), PubMed, Cochrane CENTRAL (Central Register of Controlled Trials), and Embase were searched from 2003 to the present to look at mobile health (mHealth) and attrition or dropout. Studies, either randomized controlled trials (RCTs) or observational trials, looking at chronic disease with measures of dropout were included. Meta-analysis of attrition rates was conducted in Stata, version 15.1 (StataCorp LLC). Included studies were also qualitatively synthesized to examine reasons for dropout and avenues for future research.

Results

Of 833 studies identified in the literature search, 17 were included in the review and meta-analysis. Out of 17 studies, 9 (53%) were RCTs and 8 (47%) were observational trials, with both types covering a range of chronic diseases. The pooled dropout rate was 43% (95% CI 29-57), with observational studies having a higher dropout rate (49%, 95% CI 27-70) than RCTs in more controlled scenarios, which only had a 40% dropout rate (95% CI 16-63). The studies were extremely varied, which is represented statistically in the high degree of heterogeneity (I²>99%). Qualitative synthesis revealed a range of reasons relating to attrition from app-based interventions, including social, demographic, and behavioral factors that could be addressed.

Conclusions

Dropout rates in mHealth interventions are high, but possible areas to minimize attrition exist. Reducing dropout rates will make these apps more effective for disease management in the long term.

Trial Registration

International Prospective Register of Systematic Reviews (PROSPERO) CRD42019128737; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019128737

The effect of an mHealth intervention for titration of insulin for type 2 diabetes: A pilot study

Background:

Stabilising blood glucose levels (BGL) after starting or changing insulin and related therapies can be challenging for diabetes services and the patient with type 2 diabetes. Traditionally, a credentialled diabetes educator (CDE) would talk with the patient over the phone to obtain a history of their BGLs over the previous week and provide advice on the insulin dose adjustments as required. This study trialled a smartphone application for sharing BGLs, with the ability to digitally transmit advice back to patients compared with their usual care.

Aims:

The aim of this study was to compare desirability, efficiency and ease of use.

Methods:

Participants were enrolled in either the traditional ( n=50) or Health2Sync (H2S) ( n=42) treatment group by patient preference. All insulin stabilisations were conducted by the CDE. Descriptive statistics were used for analysis.

Results:

The average total time taken to titrate patients was similar in both groups ( p>0.05), however there were fewer failure of contacts reported with H2S ( p<0.01) and time per interaction was also lower ( p<0.01). Sensitivity analysis revealed that, excluding the influence of no contacts, H2S patients had a lower average time for titration ( p<0.01). There was no difference in clinical outcomes as measured by HbA1c between the two groups ( p=0.75).

Conclusion:

We demonstrated a high acceptance and clinical utility of the H2S application. Clinicians were happy to use H2S and found it easy and convenient for most patients. Importantly, this reduced frequency of contacts with patients, time per interaction and average time for titration ( p<0.01). Patient selection for this communication intervention is important.

Implications for GP endorsement of a diabetes app with patients from culturally diverse backgrounds: a qualitative study

Although many diabetes self-management apps exist, these are not tailored for people from culturally and linguistically diverse (CALD) backgrounds. This study aimed to explore GP perceptions of how diabetes app features could help GPs better support their patients from CALD backgrounds. Twenty-five semi-structured interviews with GPs in Western Sydney explored attitudes towards a proposed app's suitability for CALD patients. Interviews were audio-recorded, transcribed and coded using Framework Analysis. Theme 1 explored the implications of perceptions that patients' health literacy is dependent on the language used. Theme 2 explored the influence of messaging from sources that share the patient's language and culture (including misinformation from community sources). Theme 3 described the suitability of the app platform for CALD patients, and its potential challenges in this group. GPs perceived that a diabetes app could be useful for providing support to patients from CALD backgrounds. Findings suggest app features should be optimised to address existing challenges that GPs face and carefully consider strategies for recruiting CALD patients. It is important that GPs feel comfortable promoting an app to their CALD patients to help increase participation rates by people in the CALD community.

Detecting the hidden burden of pre-diabetes and diabetes in Western Sydney

AIMS

Examining pre-diabetes and diabetes rates using glycated haemoglobin (HbA_1c) in emergency department (ED) and in general practice (GP) in western Sydney.

METHODS

Epidemiological study of HbA1c measurements in individuals ≥18 years receiving a blood test (1) in the hospital setting of the ED at Blacktown/Mt Druitt hospital (1/06/2016 to 31/05/2018) and (2) in primary care involving Bridgeview Medical Practice (BVMP) (1/03/2017 to 01/02/2018) as well as other general practices (June 2018 only).

RESULTS

Totals of 55,568 individuals from ED and 5911 individuals from GP. The prevalence of diabetes in tested individuals was 17.3% (n = 9704) in ED and 17.4% (n = 1027) in GP. The prevalence of pre-diabetes in ED was 30.2% (n = 16,854) and 26.6% (n = 1576) in GP. Regression controlling for age, season, and gender revealed a weekly increase of 1.1% in odds for diabetes and 1.5% for pre-diabetes (p < 0.001), in line with the yearly absolute increase of 1% in rate for both tested and coded hospital patients. In BVMP the rate of diabetes rose by 22% during the testing period from 8.9% to 11%.

CONCLUSIONS

There exists a high burden of diabetes both in hospitals and general practice. Testing in ED and general practice revealed similarly high burdens of diabetes across different areas of the healthcare system. In the appropriate hospital and primary care setting, HbA1c can be used to identify individuals with diabetes that may benefit from targeted intervention.

Factors for Supporting Primary Care Physician Engagement With Patient Apps for Type 2 Diabetes Self-Management That Link to Primary Care: Interview Study

BACKGROUND

The health burden of type 2 diabetes can be mitigated by engaging patients in two key aspects of diabetes care: self-management and regular contact with health professionals. There is a clear benefit to integrating these aspects of care into a single clinical tool, and as mobile phone ownership increases, apps become a more feasible platform. However, the effectiveness of online health interventions is contingent on uptake by health care providers, which is typically low. There has been little research that focuses specifically on barriers and facilitators to health care provider uptake for interventions that link self-management apps to the user's primary care physician (PCP).

OBJECTIVE

This study aimed to explore PCP perspectives on proposed features for a self-management app for patients with diabetes that would link to primary care services.

METHODS

Researchers conducted 25 semistructured interviews. The interviewer discussed potential features that would link in with the patient's primary care services. Interviews were audio-recorded, transcribed, and coded. Framework analysis and the Consolidated Criteria for Reporting Qualitative Research checklist were employed to ensure rigor.

RESULTS

Our analysis indicated that PCP attitudes toward proposed features for an app were underpinned by perceived roles of (1) diabetes self-management, (2) face-to-face care, and (3) the anticipated burden of new technologies on their practice. Theme 1 explored PCP perceptions about how an app could foster patient independence for self-management behaviors but could also increase responsibility and liability for the PCP. Theme 2 identified beliefs underpinning a commonly expressed preference for face-to-face care. PCPs perceived information was more motivating, better understood, and presented with greater empathy when delivered face to face rather than online. Theme 3 described how most PCPs anticipated an initial increase in workload while they learned to use a new clinical tool. Some PCPs accepted this burden on the basis that the change was inevitable as health care became more integrated. Others reported potential benefits were outweighed by effort to implement an app. This study also identified how app features can be positively framed, highlighting potential benefits for PCPs to maximize PCP engagement, buy-in, and uptake. For example, PCPs were more positive when they perceived that an app could facilitate communication and motivation between consultations, focus on building capacity for patient independence, and reinforce rather than replace in-person care. They were also more positive about app features that were automated, integrated with existing software, flexible for different patients, and included secondary benefits such as improved documentation.

CONCLUSIONS

This study provided insight into PCP perspectives on a diabetes app integrated with primary care services. This was observed as more than a technological change; PCPs were concerned about changes in workload, their role in self-management, and the nature of consultations. Our research highlighted potential facilitators and barriers to engaging PCPs in the implementation process.

Salt Iodine Variation within an Extended Guatemalan Community: The Failure of Intuitive Assumptions

Guatemalan law mandates an iodine concentration from 30 to 700 parts per million (ppm) in all table salt offered in local commerce. Forty-four specimens of salt were collected in urban and rural sectors of a county on the outskirts of the capital of Guatemala and analysed for their iodine content by an iodate titration method. The concentrations ranged from 1 to 117 ppm, (mean ± SD 26.6 ± 21.7 ppm, median 24 ppm). Salt samples with iodine in both the adequate and the inadequate ranges were found in each of five subjurisdictions (township and four hamlets), and the median concentration was equivalent at all sites, without an urban-to-rural gradient. Similarly, the mandated iodine concentration was no more likely to be found in salt packaged under a brand name with a commercial label than in salt in a plain, unlabelled package. The findings place in relief the continuing difficulties in Guatemala in the effort to provide a universally protective level of iodine in table salt.

Diabetes case finding in the emergency department, using HbA1c: an opportunity to improve diabetes detection, prevention, and care

OBJECTIVE

We assessed the efficacy of routine glycated hemoglobin (HbA1c) testing to detect undiagnosed diabetes and prediabetes in an urban Australian public hospital emergency department (ED) located in an area of high diabetes prevalence.

METHODS

Over 6 weeks, all patients undergoing blood sampling in the ED had their random blood glucose measured. If ≥5.5 mmol/L (99 mg/dL), HbA1c was measured on the same sample. HbA1c levels ≥6.5% (48 mmol/mol) and 5.7-6.4% (39-46 mmol/mol) were diagnostic of diabetes and prediabetes, respectively. Hospital records were reviewed to identify patients with previously diagnosed diabetes.

RESULTS

Among 4580 presentations, 2652 had blood sampled of which 1267 samples had HbA1c measured. Of these, 487 (38.4%) had diabetes (either HbA1c≥6.5% or a prior diagnosis), and a further 347 (27.4%) had prediabetes. Among those with diabetes, 32.2% were previously undiagnosed.

CONCLUSIONS

Routine HbA1c testing in the ED identifies a large number of people with undiagnosed diabetes and prediabetes, and provides an opportunity to improve their care.

Understanding geographical inequities in diabetes: multilevel evidence from 114,755 adults in Sydney, Australia

Multilevel analysis revealed the odds of having diabetes varied geographically by 42% among 114,755 persons. Approximately 9% of this variation was attributable to behavioural risk factors, 41% due to health status and obesity, 26% due to socioeconomic circumstances and 13% to country of birth. Contextual risk factors warrant future investigation.

Rice Fortification: An Emerging Opportunity to Contribute to the Elimination of Vitamin and Mineral Deficiency Worldwide

Vitamin and mineral deficiencies are ranked among the top causes of poor health and disability in the world. These deficiencies damage developing brains, impair learning ability, increase susceptibility to infections, and reduce the work productivity of nations. Food fortification is a sustainable, cost-effective approach to reducing vitamin and mineral deficiency. As the staple food for an estimated 3 billion people, rice has the potential to fill an obvious gap in current fortification programs. In recent years, new technologies have produced fortified rice kernels that are efficacious in reducing vitamin and mineral deficiency. There are opportunities to fortify a significant share of rice that comes from large mills supplying centralized markets and national welfare programs in major rice-growing countries. The rice export markets, which handle 30 million MT of rice annually, also present a key fortification opportunity. The cost of fortifying rice is only 1.5% to 3% of the current retail price of rice. Countries that mandate rice fortification have the strongest evidence for achieving wide coverage and impact. The Rice Fortification Resource Group (RiFoRG), a global network of public and private partners that offers technical and advocacy support for rice fortification, has a vision of promoting rice fortification worldwide. It has a targeted approach, engaging multisector partners in key countries where the opportunities are greatest and there is receptivity to early adoption of large-scale rice fortification. The challenges are real, the imperative to address them is powerful, and the opportunities to deliver the promise of rice fortification are clear.

Endemic goiter associated with high iodine intake

OBJECTIVES

This study assessed the relation of iodine content of household water to thyroid size and urinary iodine excretion in an area with high iodine concentration in the water.

METHODS

The iodine content of household water and indicators of iodine status (thyroid size and urinary iodine level) were assessed in selected villages in Jiangsu Province, China.

RESULTS

Water iodine levels were positively correlated with urinary iodine levels and indicators of thyroid size at the township level.

CONCLUSIONS

Excess iodine in household water was the likely cause of endemic goiter and elevated urinary iodine levels in the study area. This finding affects public health policy on the institution of universal salt iodization for the elimination of iodine deficiency disorders.

Thyroid volumes in US and Bangladeshi schoolchildren: comparison with European schoolchildren

OBJECTIVE

The World Health Organization (WHO) recently adopted thyroid volume ultrasonography results from European schoolchildren as the international reference for assessing iodine deficiency disorders. Our objective was to describe thyroid volumes measured by ultrasonography in US and Bangladeshi schoolchildren and compare these with European schoolchildren.

METHODS

Cross-sectional studies were performed in schoolchildren in the US (n=302) and Bangladesh (n=398). Data were collected on the following: thyroid size by palpation and ultrasonography; urinary iodine; age; sex; weight; and height.

RESULTS

Applying the new WHO thyroid volume references to the Bangladeshi children resulted in prevalence estimates of enlarged thyroid of 26% based on body surface area (BSA) and 7% based on age. In contrast, in the US children, the prevalence estimates were less than 1% for each reference. In the US children, the best single predictor of thyroid volume was BSA (R2=0.32), followed by weight (R2=0.31). Using linear regression, upper normal limits (97th percentile) of thyroid volume from US children were calculated for BSA, weight and age, and were found to be lower than the corresponding references based on BSA and age from European schoolchildren.

CONCLUSIONS

In areas with malnutrition, such as Bangladesh, the BSA reference should be preferred to the reference based on age. Results from the US children indicated that a thyroid volume reference based on weight alone would perform as well as the one based on BSA. European schoolchildren had larger thyroids than US children, perhaps due to a residual effect of iodine deficiency in the recent past in some areas in Europe.

Evaluation of automated urinary iodine methods: problems of interfering substances identified

We evaluated automated methods for measurement of urinary iodine (UI) over a range expected in iodine-replete and iodine-deficient populations. Results obtained with Technicon AutoAnalyzer II systems, based on either dialysis or acid digestion, were compared with those obtained by a manual alkaline ashing technique. Results of automated dialysis were consistently higher than those obtained by the other methods. The apparently higher concentrations of UI we measured were due to interfering substances crossing the dialysis membrane and participating in the catalytic reaction. Thiocyanate (SCN) was one endogenous substance contributing to the increased measurement of UI. For urinary SCN concentrations of 5 to 15 mg/L, the amount of overestimation in the UI measurement attributable to SCN ranged from 21.8 to 61 micrograms/L. However, SCN may account for only 40-50% of the apparent increase in UI. In samples with lower UI (less than 50 micrograms/L), interfering substances produced a 100% error in results. We conclude that the automated dialysis system should not be used to assess iodine-deficient populations. This leaves a major dilemma for researchers wanting to assess the iodine status of populations, because the automated digestion method is no longer commercially available.

Evaluation of automated urinary iodine methods: problems of interfering substances identified

We evaluated automated methods for measurement of urinary iodine (UI) over a range expected in iodine-replete and iodine-deficient populations. Results obtained with Technicon AutoAnalyzer II systems, based on either dialysis or acid digestion, were compared with those obtained by a manual alkaline ashing technique. Results of automated dialysis were consistently higher than those obtained by the other methods. The apparently higher concentrations of UI we measured were due to interfering substances crossing the dialysis membrane and participating in the catalytic reaction. Thiocyanate (SCN) was one endogenous substance contributing to the increased measurement of UI. For urinary SCN concentrations of 5 to 15 mg/L, the amount of overestimation in the UI measurement attributable to SCN ranged from 21.8 to 61 micrograms/L. However, SCN may account for only 40-50% of the apparent increase in UI. In samples with lower UI (less than 50 micrograms/L), interfering substances produced a 100% error in results. We conclude that the automated dialysis system should not be used to assess iodine-deficient populations. This leaves a major dilemma for researchers wanting to assess the iodine status of populations, because the automated digestion method is no longer commercially available.

Binding characteristics of thyroxin binding globulin in serum of normal, pregnant, and severely ill euthyroid patients

Serum from normal, pregnant, and severely ill patients was stripped of endogenous thyroid hormones and diluted 1100-fold in barbital buffer. We then used it to study the binding characteristics of thyroxin binding globulin (TBG), noting significant differences in binding capacities among the groups. The mean (+/- SD) triiodothyronine/thyroxin ratio for binding capacity was 18 +/- 4 for normal subjects. The ratio was significantly increased in pregnant patients, 21 +/- 4 (p less than 0.05), and significantly lower in severely ill patients, 12 +/- 4 (p less than 0.05). When serum was diluted before assay, to give a uniform TBG concentration among groups, these apparent differences in binding characteristics were eliminated. It therefore is unlikely that different molecular species of TBG account for the variations in binding characteristics in these clinical states. Apparently, the distribution of thyroxin and triiodothyronine among the binding sites on TBG changes with variations in TBG concentration. This may explain the discrepancies observed in the concentrations of free thyroid hormones as estimated by various methodologies.

Binding characteristics of thyroxin binding globulin in serum of normal, pregnant, and severely ill euthyroid patients

Serum from normal, pregnant, and severely ill patients was stripped of endogenous thyroid hormones and diluted 1100-fold in barbital buffer. We then used it to study the binding characteristics of thyroxin binding globulin (TBG), noting significant differences in binding capacities among the groups. The mean (+/- SD) triiodothyronine/thyroxin ratio for binding capacity was 18 +/- 4 for normal subjects. The ratio was significantly increased in pregnant patients, 21 +/- 4 (p less than 0.05), and significantly lower in severely ill patients, 12 +/- 4 (p less than 0.05). When serum was diluted before assay, to give a uniform TBG concentration among groups, these apparent differences in binding characteristics were eliminated. It therefore is unlikely that different molecular species of TBG account for the variations in binding characteristics in these clinical states. Apparently, the distribution of thyroxin and triiodothyronine among the binding sites on TBG changes with variations in TBG concentration. This may explain the discrepancies observed in the concentrations of free thyroid hormones as estimated by various methodologies.