Peer Reviewed: Variation in Quality of Diabetes Care at the Levels of Patient, Physician, and Clinic

Introduction

We studied variance in glycated hemoglobin (HbA1c) values among adults with diabetes to identify variation in quality of diabetes care at the levels of patient, physician, and clinic, and to identify which levels contribute the most to variation and which variables at each level are related to quality of diabetes care.

Methods

Study subjects were 120 primary care physicians and their 2589 eligible adult patients with diabetes seen at 18 clinics. The dependent variable was HbA1c values recorded in clinical databases. Multivariate hierarchical models were used to partition variation in HbA1c values across the levels of patient, physician, or clinic and to identify significant predictors of HbA1c at each level.

Results

More than 95% of variance in HbA1c values was attributable to the patient level. Much less variance was seen at the physician and clinic level. Inclusion of patient and physician covariates did not substantially change this pattern of results. Intensification of pharmacotherapy (t = −7.40, P < .01) and  patient age (t = 2.10, P < .05) were related to favorable change in HbA1c. Physician age, physician specialty, number of diabetes patients per physician, patient comorbidity, and clinic assignment did not predict change in HbA1c value. The overall model with covariates explained 11.8% of change in HbA1c value over time.

Conclusion

These data suggest that most variance in HbA1c values is attributable to patient factors, although physicians play a major role in some patient factors (e.g., intensification of medication). These findings may lead to more effective care-improvement strategies and accountability measures.     

Dosimetric consequences of intrafraction prostate motion

PURPOSE: To analyze characteristics of intrafraction prostate motion, monitored using the Calypso system, and investigate dosimetric consequences of the motion for different clinical target volume (CTV) to planning target volume (PTV) margins. METHODS AND MATERIALS: Motion characteristics were analyzed for 1,267 tracking sessions and 35 patients. Using prostate-PTV margins of 0, 1, 2, 3, and 5 mm, dose metrics for the prostate gland, bladder, and rectum were evaluated for scenarios including patient population, individual patients showing the greatest motion during the course of treatment, and the individual session with the largest overall movement. Composite dose distributions incorporating motion blurring were calculated by convolving static intensity-modulated radiotherapy plans with corresponding motion probability functions. RESULTS: For prostate-PTV margins of 2 mm or greater, intrafraction motion did not compromise prostate dose coverage for either the patient population or individual patients. For the patient showing the largest overall movement, the prostate equivalent uniform dose was reduced by only 17.4 cGy (0.23%), and the minimum prostate dose remained greater than 95% of the nominal dose. For margins less than 2 mm, the prostate dose-volume histogram in the same patient was slightly compromised, and the equivalent uniform dose was reduced by 38.5 cGy (0.51%). Sparing of the bladder and rectum was improved substantially by reducing margins. CONCLUSIONS: Although significant motion can be observed during individual fractions, the dosimetric consequences are insignificant during a typical course of radiotherapy (30-40 fractions) with CTV-PTV margins of 2 mm or greater provided that the Calypso system is applied for pretreatment localization. Further reduction of the margin is possible if intrafraction realignment is performed.     

Resistance to valproic acid as predictor of treatment resistance in genetic generalized epilepsies

This study aimed at defining clinical predictors of drug resistance in adults with genetic generalized epilepsy (GGE) who were treated with a broad spectrum of antiepileptic drugs. Of a cohort of 137 unselected adult GGE patients with long‐term follow up, clinical and demographic data, putative prognostic factors (e.g., psychiatric comorbidities, electroencephalography [EEG]), treatment response, and data indicative of social status were collected. Fifty‐eight patients had seizures within the past year. Thirty‐three patients met the definition of “drug‐resistant epilepsy” according to the International League Against Epilepsy (ILAE) definition. Psychiatric comorbidities, age at first diagnosis, and absences were associated with worse seizure control, whereas focal changes in EEG remained without prognostic impact. Resistance to valproic acid was the most important prognostic factor for refractory seizures. Resistance to valproic acid had a specificity of 100% to identify patients with drug resistance and correlated strongly with bad social outcome and seizure burden. Conversely, 21.2% of all patients with refractory seizures according to the ILAE definition later became seizure free (mainly with valproic acid). Our data suggest that “drug resistant GGE” must not be declared unless patients were adequately treated with valproic acid, and advocate resistance to valproic acid as a new clinical biomarker for drug‐resistant GGE. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here .     

Influenza vaccination health impact and cost effectiveness among adults aged 50 to 64 and 65 and older

BACKGROUND: Influenza causes approximately 36,000 deaths per year in the United States despite the presence of an effective vaccine. This assessment of the value of influenza vaccination to the U.S. population is part of an update to the 2001 ranking of clinical preventive services recommended by the U.S. Preventive Services Task Force. The forthcoming ranking will include the new recommendation of the Advisory Committee on Immunization Practices to extend influenza vaccination to adults aged 50 to 64 years. METHODS: This service is evaluated on the two most important dimensions: burden of disease prevented and cost effectiveness. Study methods, described in a companion article, are designed to ensure consistency across many services. RESULTS: Over the lifetime of a birth cohort of 4 million, it is estimated that about 275,000 quality-adjusted life years (QALYs) would be saved if influenza vaccination were offered annually to all people after age 50. Eighty percent of the QALYs saved (220,000) would be achieved by offering the vaccine only to persons aged 65 and older. In year 2000 dollars, the cost effectiveness of influenza vaccination is $980 per QALY saved in persons aged 65 and older, and $28,000 per QALY saved in persons aged 50 to 64. When the costs of patient time and travel are excluded, the cost effectiveness ratio of vaccinating 50- to 64-year-olds decreases to $7200 per QALY saved, and vaccinating those aged 65 and older saves $17 per person vaccinated. CONCLUSIONS: Influenza vaccination is a high-impact, cost-effective service for persons aged 65 and older. Vaccinations are also cost effective for persons aged 50 to 64.     

The risk of “getting worse” after lumbar microdiscectomy

A frequent concern among patients operated for lumbar disc herniation is the risk of getting worse. To give an evidence-based estimate of the risk for worsening has been difficult, since previous studies have been more focused on unfavourable outcome in general, rather than on deterioration in particular. In this prospective study of 180 patients, we report the frequency of and the risk factors for getting worse after first time lumbar microdiscectomy. Follow-up time was 12 months. Primary outcome measure was the Oswestry disability index, assessing functional status and health-related quality of life. Of the patients 4% got worse. Independent risk factors of deterioration were a long duration of sick leave and a better functional status and quality of life prior to operation. We conclude that the risk of deterioration is small, but larger if the patient has been unable to work despite relatively small health problems. This study also demonstrates that changes in instrument scores should be reported, so that an accurate failure rate can be assessed.     

Diabetic patients who smoke: are they different?

BACKGROUND We wanted to identify differences between diabetic patients who smoke and those who do not smoke to design more effective strategies to improve their diabetes care and encourage smoking cessation.