Prospective evaluation of a complex public health intervention: lessons from an initial and follow-up cross-sectional survey of the tuberculosis strain typing service in England.

BACKGROUND: The national tuberculosis strain typing service (TB-STS) was introduced in England in 2010. The TB-STS involves MIRU-VNTR typing of isolates from all TB patients for the prospective identification, reporting and investigation of TB strain typing clusters. As part of a mixed-method evaluation, we report on a repeated cross-sectional survey to illustrate the challenges surrounding the evaluation of a complex national public health intervention. METHODS: An online initial and follow-up questionnaire survey assessed the knowledge, attitudes and practices of public health staff, physicians and nurses working in TB control in November 2010 and March 2012. It included questions on the implementation, experience and uptake of the TB-STS. Participants that responded to both surveys were included in the analysis. RESULTS: 248 participants responded to the initial survey and 137 of these responded to the follow-up survey (56% retention). Knowledge: A significant increase in knowledge was observed, including a rise in the proportion of respondents who had received training (28.6% to 67.9%, p = 0.003), and the self-rated knowledge of how to use strain typing had improved ('no knowledge' decreased from 43.2% to 27.4%). Attitudes: The majority of respondents found strain typing useful; the proportion that reported strain typing to be useful was similar across the two surveys (95.7% to 94.7%, p = 0.67). Practices: There were significant increases between the initial and follow-up surveys in the number of respondents who reported using strain typing (57.0% to 80.5%, p < 0.001) and the proportion of time health protection staff spent on investigating TB (2.74% to 7.08%, p = 0.04). CONCLUSIONS: Evaluation of a complex public health intervention is challenging. In this example, the immediate national roll-out of the TB-STS meant that a controlled survey design was not possible. This study informs the future development of the TB-STS by identifying the need for training to reach wider professional groups, and argues for its continuation based on service users' perception that it is useful. By highlighting the importance of a well-defined sampling frame, collecting baseline information, and including all stakeholders, it provides lessons for the implementation of similar services in other countries and future evaluations of public health interventions.

Simple Nephrectomy in a Tertiary Care Safety Net Hospital-Patient Characteristics, Causes, Cost, and Renal Function Implications.

OBJECTIVE: To evaluate factors associated with simple nephrectomy at a safety net hospital with a diverse patient population and large catchment area. Simple nephrectomy is an underreported surgery. Performance of simple nephrectomy may represent a failure of management of underlying causes. METHODS: We performed a retrospective review of simple nephrectomies performed at a major urban safety net hospital from 2014 to 2019. Detailed demographic, surgical, and renal functional outcomes were abstracted. We assessed the medical and social factors leading to performance of simple nephrectomy and report contemporaneous perception of preventability of the simple nephrectomy by the surgeon. RESULTS: Eighty-five patients underwent simple nephrectomy during the study period; 55% were non-white, 77% were women, and the median age at time of surgery was 46 years. The most common medical factors contributing to simple nephrectomy were stone disease in 55.3%, followed by retained ureteral stent (30.6%) and stricture (30.6%). The most common social factors were lack of insurance (58.5%), substance abuse issues (32.3%), mental health issues (24.6%), and immigration status (18.5%). In 38.8% of cases, the provider felt the surgery was preventable if medical factors leading to simple nephrectomy were properly addressed. CONCLUSIONS: Simple nephrectomy is a common surgery in the safety net hospital setting. Both medical and sociologic factors can lead to simple nephrectomy, and awareness of these factors can lead efforts to mitigate them. This review has led to the implementation of strategies to minimize occurrences of retained stents in our patients.

Effect of study design and setting on tuberculosis clustering estimates using Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeats (MIRU-VNTR): a systematic review.

OBJECTIVES: To systematically review the evidence for the impact of study design and setting on the interpretation of tuberculosis (TB) transmission using clustering derived from Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeats (MIRU-VNTR) strain typing. DATA SOURCES: MEDLINE, EMBASE, CINHAL, Web of Science and Scopus were searched for articles published before 21st October 2014. REVIEW METHODS: Studies in humans that reported the proportion of clustering of TB isolates by MIRU-VNTR were included in the analysis. Univariable meta-regression analyses were conducted to assess the influence of study design and setting on the proportion of clustering. RESULTS: The search identified 27 eligible articles reporting clustering between 0% and 63%. The number of MIRU-VNTR loci typed, requiring consent to type patient isolates (as a proxy for sampling fraction), the TB incidence and the maximum cluster size explained 14%, 14%, 27% and 48% of between-study variation, respectively, and had a significant association with the proportion of clustering. CONCLUSIONS: Although MIRU-VNTR typing is being adopted worldwide there is a paucity of data on how study design and setting may influence estimates of clustering. We have highlighted study design variables for consideration in the design and interpretation of future studies.