Evidence-based Estimates Research Articles

EFSA statement on the risk posed to humans by a vitamin B2 produced by a genetically modified strain of Bacillus subtilis used as a feed additive.

The detection of recombinant DNA in a vitamin B2 used as a feed additive was notified by the Belgian national authorities on 2 October 2018 via the Rapid Alert System for Food and Feed (RASFF). The European Commission requested scientific advice from EFSA on the risk posed to humans by the presence of genetically modified material in the feed additive, particularly with regard to antimicrobial resistance (AMR). EFSA assessed the analytical data from RASFF regarding the presence of AMR genes in both additive and feed. Samples of the additive and feed tested positive for the presence of DNA of a genetically modified Bacillus subtilis. The results were compatible with, but did not demonstrate the presence of, a full‐length chloramphenicol resistance gene. No information was made available on the presence of other AMR genes or viable cells of the B. subtilis. The statement provides a risk assessment pathway indicating the events needed to produce adverse human health effects from the presence of AMR genes in feed additives. Data on the likelihood of occurrence of all events are needed to produce an evidence‐based estimate of the risk. All the events are theoretically possible, but there are no scientific data available to estimate the probability of each taking place. Moreover, there is no evidence of the presence of full‐length AMR gene(s) in the vitamin B2 additive or feed; thus, it is not clear whether the first step towards AMR gene transfer is fulfilled. The sole presence of fragments of AMR genes in a feed additive is not a risk. If a full‐length AMR gene were present in a feed additive, it could lead to risks linked to its transmission to pathogens via the food chain and/or to the environmental spread of AMR bacteria/genes, potentially contributing to the environmental reservoir of AMR determinants.

Is the Importance of Heart Dose Overstated in the Treatment of Non-Small Cell Lung Cancer? A Systematic Review of the Literature

Some recent studies have suggested a relationship between cardiac dose and mortality in non-small cell lung cancer (NSCLC), but others have reported conflicting data. The goal of this study was to conduct a systematic review and meta-analysis to provide an evidence-based estimate of the relationship between cardiac dose and mortality in these patients. A systematic review of MEDLINE (PubMed) and Embase databases (inception to January 2018) was performed according to PRISMA guidelines. Studies that evaluated cardiac dosimetric factors in patients with NSCLC and included outcomes of cardiac events, cardiac mortality, and/or overall survival were identified. From 5614 patients across 22 studies, a total of 214 cardiac dosimetric parameters (94 unique) were assessed as possible predictors of cardiac toxicity or death. Assessed predictors included general (eg, mean heart dose [MHD]), threshold-based (eg, heart V5), and anatomic-based (eg, atria, ventricles) dosimetric factors. The most commonly analyzed parameters were MHD, heart V5, and V30. Most studies did not make corrections for multiplicity of testing. For overall survival, V5 was found to be significant on multivariable analysis (MVA) in 1 of 11 studies and V30 in 2 of 12 studies; MHD was not significant in any of 8 studies. For cardiac events, V5 was found to be significant on multivariable analysis in 1 of 2 studies, V30 in 1 of 3 studies, and MHD in 2 of 4 studies. A meta-analysis of the data could not be performed because most negative studies did not report effect estimates. Consistent heart dose-volume parameters associated with overall survival of patients with NSCLC were not identified. Multiplicity of testing is a major issue and likely inflates the overall risk of type I errors in the literature. Future studies should specify predictors a priori, correct for multiplicity of testing, and report effect estimates for nonsignificant variables.

A Look Over Through Survey To Analyze and Compare Accuracy of Existing Estimation Technologies on Basis of Project Size and Explore the Reasons of Inaccuracy in NCR Software Industries

Although after giving a lot of attention to software cost estimation since 1990, accuracy in effort and time estimation is still a vital and challenging area. It is very important to investigate the accuracy of cost effort estimation, the current estimation techniques, and which factors affect to adopt estimation methods in software industries of NCR. This paper analyzed 596 software development team member’s data on likert scale and conducted questionnaire survey on various organizations to investigate the above information. The survey presents the current scenario related to small and large software project estimation in NCR and provides evidence-based estimation improvement suggestions. Our survey results suggest accuracy of estimation methods and scheduling that large projects were more deviated, comparison with previous studies, satisfaction with the current project estimation methods, Expert judgement and Planning poker techniques are widely used and very few developers (46%) used theory based methods.

Adjusted mortality rates attributable to Alzheimer's disease dementia, Brazil, 2009-2013.

This paper provides estimates of mortality rates from Alzheimer's disease dementia (AD) in the elderly Brazilian population. Data were obtained from the 2010 Population Census by Brazilian Institute of Geography and Statistics (IBGE) and microdata on mortality in Brazil's 27 state capitals recorded in the Brazilian Mortality Information System (SIM) for the population 65 years or older by place of residence for the years 2009 to 2013. Corrections were obtained for underreporting of mortality, and final adjustments were made to the specific mortality rates based on Bayesian methods with prior probability distributions built on the basis of information obtained from a meta-analysis. The mortality rates from all dementias and from AD in Brazil were higher than in developed countries. The mortality rates from Alzheimer's disease in 2013 were 140.03 (95%CI: 117.05; 166.4) and 127.07 (95%CI: 103.74; 149.62) per 100,000 inhabitants, respectively, in men and women. The contribution of AD to mortality in elderly Brazilians was 4.4% (95%CI: 3.25; 5.72) in the group with 0 to 3 years of schooling, independently of age and sex. The study aimed to increase knowledge on corrected estimates of mortality rates from Alzheimer's disease based on vital statistics, providing more precise and pertinent evidence-based estimates.

Prevalence of autism spectrum disorder in Indian children: A systematic review and meta-analysis.

Autism spectrum disorder (ASD) is a developmental disability and is of public health importance. It affects not only the child and the family. It also has direct and indirect cost implications on the nation that are incurred in providing health care, support for education, and rehabilitative services. There is a lack of evidence-based estimate of the population prevalence of ASD in India. Therefore, this systematic review was aimed at determining the prevalence of ASD in the Indian population. We conducted a systematic review and meta-analysis of the published studies evaluating the prevalence of ASD in the community setting. A search within the published literature was conducted from different databases (PubMed, OvidSP, and EMBASE). The analysis of data was done using STATA MP12 (StataCorp, College Station, TX, USA). Four studies were included in this systematic review. Of the four included studies, one had studied both urban and rural populations, and the other three had studied the urban populations only. The study from the rural setting showed a pooled percentage prevalence of 0.11 [95% confidence interval (CI) 0.01-0.20] in children aged 1-18 years; and, four studies conducted in the urban setting showed a pooled percentage prevalence of 0.09 (95% CI 0.02-0.16) in children aged 0-15 years. The scarcity of high-quality population-based epidemiological studies on ASD in India highlights an urgent need to study the burden of ASD in India. The proper acquisition of data related to the prevailing burden of ASD in India would lead to a better development of rehabilitative services in our country.

Is the Importance of Heart Dose Overstated in Non-Small Cell Lung Cancer? A Systematic Review of the Literature

Thoracic radiation has been associated with increased cardiac toxicity and mortality in studies of patients with breast cancer and Hodgkin Lymphoma. However, this impact is not well studied in patients with non-small cell lung cancer (NSCLC). Recent studies have suggested a relationship between cardiac dose and mortality, but the strength of the relationship and the optimal dosimetric predictors are unknown. The goal of this study was to conduct a systematic review and meta-analysis to provide an evidence-based estimate of the relationship between cardiac dose and mortality in patients with NSCLC. A systematic review of MEDLINE (PubMed) and Embase databases (inception to January 2018) according to PRISMA guidelines was performed. Studies which evaluated cardiac dosimetric factors in patients with NSCLC and which include outcomes of cardiac events, cardiac mortality and overall survival were identified. After the initial search (n= 461), studies were screened by title (n= 78), then by abstract (n= 33), and then included for full text review (n=22). From 6240 patients across 22 studies, a total of 214 cardiac dosimetric parameters (84 unique parameters) were assessed as possible predictors of cardiac toxicity or death, with a mean of 10 dosimetric factors assessed per study. Predictors assessed included general dosimetric factors (e.g. mean and maximum heart doses), factors based on threshold doses (e.g. heart V5), and factors based on doses to anatomic structures or sub-volumes (e.g. atria, ventricles). The most commonly analyzed parameters were mean heart dose (MHD), heart V5 and V30. Most studies did not make corrections for multiplicity of testing. For the endpoint of overall survival, V5 was found to be significant on multivariable analysis (MVA) in 1 of 11 studies, V30 significant in 2 of 12 studies and MHD was not significant in any of 8 studies. For the endpoint of cardiac events, V5 was found to be significant on MVA in 2 of 4 studies, V30 in 1 of 3 studies, and MHD in 2 of 4 studies. There was little overlap in the sub-volume parameters included in multivariable models across studies. A meta-analysis of the data could not be performed, as most negative studies did not report effect estimates (e.g. hazard ratios) and could not be meta-analyzed. Heart dose-volume constraints are not consistently associated with overall survival of NSCLC patients. Multiplicity of testing is a major issue and likely inflates the overall rate of type I error in the literature. Future studies should specify predictors a priori, correct for multiplicity of testing, and report effect estimates for non-significant variables.

Comparison of Physical Fitness and Cardiopulmonary Exercise Test Performance Using Arm Versus Leg Cycling in Patients With Cardiovascular or Pulmonary Disease–A Systematic Review and Meta-analysis

Purpose: Alternative modes of cardiopulmonary exercise testing are needed and an arm cycle (AC) is a promising alternative to the gold standard of the leg cycle (LC). The aim of this study was to undertake a systematic review comparing maximal oxygen consumption (VO2max) obtained from AC and LC in patient populations with cardiovascular disease (CVD) and pulmonary disease (PD). Methods: A systematic review was undertaken with literature searches on December 5, 2016. Studies were included if they directly compared aerobic capacity values obtained from AC and LC in patients with CVD or PD. Results across studies were pooled using random effects meta-analysis and univariate meta-regression were used to assess potential associations between variables. Results: A total of 14 studies in 411 patients were included. On average, VO2max of LC exceeded AC mean difference by 3.48 mL·kg−1·min−1, (95% confidence interval [CI]: 1.94, 5.03) and a mean AC/LC ratio of 0.83, (95% CI: 0.77, 0.90). VO2max differences between AC and LC were similar in patients with CVD compared with PD but were found to be higher in older individuals and those with higher VO2max. Conclusions: Although AC offers an important alternative form of exercise testing for patients with CVD or PD, clinicians must take into account that VO2max values obtained from AC are consistently lower than those obtained on LC. However, the results of this article offer an evidence-based estimation for the proportional differences between AC values and LC values for groups with CVD or groups with PD.

Historical overview of development in methods to estimate burden of disease due to congenital disorders

Congenital disorders (often also called birth defects) are an important cause of mortality and disability. They encompass a wide range of disorders with differing severity that can affect any aspect of structure or function. Understanding their epidemiology is important in developing appropriate services both for their prevention and treatment. The need for epidemiological data on congenital disorders has been recognised for many decades. Here, we provide a historical overview of work that has led to the development of the Modell Global Database of Congenital Disorders (MGDb)—a tool that can be used to generate evidence-based country, regional and global estimates of the birth prevalence and outcomes of congenital disorders.

Incidence and Method of Suicide in Hospitals in the United States

There are no reliable estimates of hospital inpatient suicides in the United States. Understanding the rate and the methods used in suicides is important to guide prevention efforts. This study analyzed two national data sets to establish an evidence-based estimate of hospital inpatient suicides and the methods used. The study is designed as a cross-sectional analysis of data from 27 states reporting to the National Violent Death Reporting System (NVDRS) for 2014-2015, and from hospitals reporting to The Joint Commission's Sentinel Event (SE) Database from 2010 to 2017. Categorical variables and qualitative reviews of event narratives were used to identify and code suicide events occurring during hospital inpatient treatment. Based on the hospital inpatient suicides reported in the NVDRS during 2014-2015, 73.9% of which occurred during psychiatric treatment, it is estimated that between 48.5 and 64.9 hospital inpatient suicides occur per year in the United States. Of these, 31.0 to 51.7 are expected to involve psychiatric inpatients. Hanging was the most common method of inpatient suicide in both the NVDRS and SE databases (71.7% and 70.3%, respectively). The estimated number of hospital inpatient suicides per year in the United States ranges from 48.5 to 64.9, which is far below the widely cited figure of 1,500 per year. Analysis of inpatient suicide methods suggests that hospital prevention efforts should be primarily focused on mitigating risks associated with hanging, and additional suicide prevention efforts may be best directed toward reducing the risk of suicide immediately following discharge.

Medications and pregnancy: The role of community pharmacists - A descriptive study.

BackgroundSafe use of medications during pregnancy requires a comprehensive understanding of risk-benefit profiles for individual treatments. Pharmacists are supported in this aspect by clinical information agencies (e.g. MotherSafe, a telephone-based teratogen information service) and reference texts. To what extent and for what reasons Australian pharmacists utilise these services/resources are yet unknown. Further, debate on replacement of conventionally defined medication safety in pregnancy categories (A, B1-3, C, D, X) by narratively stated safety evidence may affect pharmacists’ routine practice. This study aimed to gauge pharmacists’ experiences and resource needs in undertaking support roles regarding gestational drug use.MethodsSemi-structured interviews (audio-recorded or documented using field notes) were performed with community pharmacists in Australia and transcribed verbatim. Inductive thematic analysis was conducted using the NVivo software (Version 11, QSR International).ResultsData saturation was achieved with 24 interviews. Qualitative data yielded 5 emergent themes: barriers to effective counselling, patient trust, risk perception, role definition and practice support needs. Overall, participants relied on pregnancy categories, were risk averse and cautious in offering advice. Currently available data for unclassified and category B therapeutic agents (limited human data) were deemed inadequate. Reluctance to use the proposed narrative system was also expressed.DiscussionThis study highlights key barriers in the provision of maternal care by pharmacists and the potential tension present if the existing category system is replaced by a narrative one. These need to be addressed through training and development of practice support resources to enhance pharmacists’ skills in evidence-based risk estimation and communication.

Estimating the Health and Economic Impacts of Changes in Local Air Quality.

To demonstrate the benefits-mapping software Environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE), which integrates local air quality data with previously published concentration-response and health-economic valuation functions to estimate the health effects of changes in air pollution levels and their economic consequences. We illustrate a local health impact assessment of ozone changes in the 10-county nonattainment area of the Dallas-Fort Worth region of Texas, estimating the short-term effects on mortality predicted by 2 scenarios for 3 years (2008, 2011, and 2013): an incremental rollback of the daily 8-hour maximum ozone levels of all area monitors by 10 parts per billion and a rollback-to-a-standard ambient level of 65 parts per billion at only monitors above that level. Estimates of preventable premature deaths attributable to ozone air pollution obtained by the incremental rollback method varied little by year, whereas those obtained by the rollback-to-a-standard method varied by year and were sensitive to the choice of ordinality and the use of preloaded or imported data. BenMAP-CE allows local and regional public health analysts to generate timely, evidence-based estimates of the health impacts and economic consequences of potential policy options in their communities.

Estimating the incubation period of acute Q fever, a systematic review.

Estimates of the incubation period for Q fever vary substantially between different reviews and expert advice documents. We systematically reviewed and quality appraised the literature to provide an evidence-based estimate of the incubation period of the Q fever by the aerosolised infection route. Medline (OVIDSP) and EMBASE were searched with the search limited to human studies and English language. Eligible studies included persons with symptomatic, acute Q fever, and defined exposure to Coxiella burnetti. After review of 7115 titles and abstracts, 320 records were screened at full-text level. Of these, 23 studies contained potentially useful data and were quality assessed, with eight studies (with 403 individual cases where the derivation of incubation period was possible) being of sufficient quality and providing individual-level data to produce a pooled summary. We found a median incubation period of 18 days, with 95% of cases expected to occur between 7 and 32 days after exposure.

Do Physical Activities Trigger Flare-ups During an Acute Low Back Pain Episode?: A Longitudinal Case-Crossover Feasibility Study.

Prospective, longitudinal case-crossover study. The aim of this study was to determine whether physical activities trigger flare-ups of pain during the course of acute low back pain (LBP). .: There exist no evidence-based estimates for the transient risk of pain flare-ups associated with specific physical activities, during acute LBP. Participants with LBP of duration <3 months completed frequent, Internet-based serial assessments at both 3- and 7-day intervals for 6 weeks. At each assessment, participants reported whether they had engaged in specific physical activity exposures, or experienced stress or depression, during the past 24 hours. Participants also reported whether they were currently experiencing a LBP flare-up, defined as "a period of increased pain lasting at least 2 hours, when your pain intensity is distinctly worse than it has been recently." Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for associations between potential triggers during the past 24 hours, and the risk of LBP flare-ups, using conditional logistic regression. Of 48 participants followed longitudinally, 30 participants had both case ("flare") and control periods and contributed data to the case-crossover analysis. There were 81 flare periods and 247 control periods, an average of 11 periods per participant. Prolonged sitting (>6 hours) was the only activity that was significantly associated with flare-ups(OR 4.4, 95% CI 2.0-9.7; P < 0.001). Having either stress or depression was also significantly associated with greater risk of flare-ups (OR 2.5, 95% CI 1.0-6.0; P = 0.04). In multivariable analyses, prolonged sitting (OR 4.2, 95% CI 1.9-9.1; P < 0.001), physical therapy (PT) (OR 0.4, 95% CI 0.1-1.0; P = 0.05), and stress/depression (OR 2.8, 95% CI 1.2-6.7; P = 0.02) were independently and significantly associated with LBP flare-up risk. Among participants with acute LBP, prolonged sitting (>6 hours) and stress or depression triggered LBP flare-ups. PT was a deterrent of flare-ups. 2.

Ecological Fiscal Transfers in Europe – Evidence-Based Design Options for a Transnational Scheme

Ecological Fiscal Transfers (EFT) have recently gained attention as a promising instrument addressing public authorities to provide incentives for nature conservation. In parallel, both the EU and various European countries are exploring new mechanisms to mobilise funding to support biodiversity conservation. We develop a proposal for an EFT design within the supranational context of the EU and assess its potential effects with evidence-based estimates. We i) provide both a theoretical underpinning and a synthesis of the current EFT schemes and EU Nature Directives, ii) propose a model for EFT implementation within the existing EU funding mechanisms based on quantitative and qualitative conservation indicators, iii) analyse how resulting payments would be (spatially) distributed among European regions, and iv) discuss the model outcomes in terms of ecological effectiveness, distributive effects and cost-effectiveness. We thereby contribute to the debate about how to better integrate ecological public functions within multi-level and supra-national governance structures.

Stability of Illicit Drugs as Biomarkers in Sewers: From Lab to Reality.

Systematic sampling and analysis of wastewater samples are increasingly adopted for estimating drug consumption in communities. An understanding of the in-sewer transportation and transformation of illicit drug biomarkers is critical for reducing the uncertainty of this evidence-based estimation method. In this study, biomarkers stability was investigated in lab-scale sewer reactors with typical sewer conditions. Kinetic models using the Bayesian statistics method were developed to simulate biomarkers transformation in reactors. Furthermore, a field-scale study was conducted in a real pressure sewer pipe with the systematical spiking and sampling of biomarkers and flow tracers. In-sewer degradation was observed for some spiked biomarkers over typical hydraulic retention time (i.e., a few hours). Results indicated that sewer biofilms prominently influenced biomarker stability with the retention time in wastewater. The fits between the measured and the simulated biomarkers transformation demonstrated that the lab-based model could be extended to estimate the changes of biomarkers in real sewers. Results also suggested that the variabilities of biotransformation and analytical accuracy are the two major contributors to the overall estimation uncertainty. Built upon many previous lab-scale studies, this study is one critical step forward in realizing wastewater-based epidemiology by extending biomarker stability investigations from laboratory reactors to real sewers.

A systematic review and meta-analysis of utility estimates in melanoma.

Health-related quality of life (HRQOL) in melanoma is affected by cancer stage. Previous studies have reported limited data on utility-based HRQOL. To determine pooled estimates of utility-based HRQOL (utilities) for people with American Joint Cancer Committee stage I/II, III or IV melanoma for use in economic evaluations. We performed a systematic review, meta-analysis and metaregression of utilities for patients with melanoma. HRQOL scores reported with the QLQ-C30, SF-36, SF-12, FACT-G and FACT-M instruments were converted to utilities using published mapping algorithms. Meta-analysis was used to calculate mean utilities. Metaregression was used to examine the effects of baseline patient and study characteristics. We identified 33 studies reporting 213 utilities. From meta-analyses, the mean utility for stage I/II melanoma was 0·97 [95% confidence interval (CI) 0·90-0·98]; for stage III melanoma it was 0·77 (95% CI 0·70-0·83); for stage III/IV 0·76 (95% CI 0·76-0·77); and for stage IV melanoma 0·76 (95% CI 0·71-0·81). The difference in utility between stage III and stage IV was not statistically significant (P=0·52). For patients with stage I/II, the utility estimate at the time of surgery was 0·77 (95% CI 0·75-0·79), and at 3-12months postsurgery it was 0·85 (95% CI 0·84-0·86). Utility estimates for patients with stage IV melanoma were 0·65 (95% CI 0·62-0·69) during the first 3months of treatment and 0·83 (95% CI 0·81-0·86) at 4-12months on treatment. For patients with stage IV melanoma treated with chemotherapy, the utility estimate was 0·52 (95% CI 0·51-0·52), while for those treated with targeted therapy it was 0·83 (95% CI 0·82-0·85). These robust, evidence-based estimates of health state utility can be used in economic evaluations of new treatments for patients with early-stage or advanced-stage melanoma.

Proposed global drooping and wrinkles classification and scoring system for aging face with validation and experience on 54 Indian subjects.

Aging is an inevitable biological change, but understanding the process of aging of face is important to customize the treatment options for facial rejuvenation. Evidence-based estimation of global facial aging is necessary for the validation of various treatment modalities. Classification and implementation of a scoring system for aging face based upon volume loss and surface changes as evident by drooping of different areas of the face and appearance of fine and deep wrinkles, respectively, and to apply this drooping-wrinkles classification on 54 participants to evaluate and understand the validity of scoring. An observational study was conducted, and scores were calculated based on 13 parameters (7 areas of drooping and 6 areas of wrinkles on the face) at Aura Skin Institute, Chandigarh, India. Accordingly, age was divided in different age groups followed by clinical estimation of facial age and calculation of scores. According to our classification and scoring system, 61% (33 out of 54) of the participants were correlated with their chronological age group. Out of the remaining 21 (39%) participants who were aging faster, 13 (24%) were in the age group of 25-35 years. Approximately one-fourth of the patients in the age groups 36-45 and 46-55 years were aging faster. Only 1 patient had scores showing younger age in comparison to chronological age. Overall, there was a good correlation between the calculated score and the chronological age of patients. Moreover, a gradual increase in scores was noticed with increasing age groups. This is a new clinical classification and scoring system for facial age which is much easier to apply in daily clinical practice for easy calculation of baseline scores and customizing their antiaging treatment options. Moreover, it will also make it easier to compare the efficacy of treatment in their future follow-ups. The limitation of this study is that it has been proposed for all skin types but validation has been done only for Indian participants.

Wastewater Analysis for Community-Wide Drugs Use Assessment.

Wastewater-based epidemiology (WBE) complements existing epidemiology-based estimation techniques and provides objective, evidence-based estimates of illicit drug use. After consumption, biomarkers - drugs and their metabolites - excreted to toilets and flushed into urban sewer networks can be measured in raw wastewater samples. The quantified loads can serve as an estimate for the collective consumption of all people contributing to the wastewater sample. This transdisciplinary approach, further explained in this chapter, has developed, matured and is now established for monitoring substances such as cocaine and amphetamine-type stimulants. Research currently underway is refining WBE to new applications including new psychoactive substances (NPS).

Methods for Sexually Transmitted Disease Prevention Programs to Estimate the Health and Medical Cost Impact of Changes in Their Budget.

The purpose of this article was to describe methods that sexually transmitted disease (STD) programs can use to estimate the potential effects of changes in their budgets in terms of disease burden and direct medical costs. We proposed 2 distinct approaches to estimate the potential effect of changes in funding on subsequent STD burden, one based on an analysis of state-level STD prevention funding and gonorrhea case rates and one based on analyses of the effect of Disease Intervention Specialist (DIS) activities on gonorrhea case rates. We also illustrated how programs can estimate the impact of budget changes on intermediate outcomes, such as partner services. Finally, we provided an example of the application of these methods for a hypothetical state STD prevention program. The methods we proposed can provide general approximations of how a change in STD prevention funding might affect the level of STD prevention services provided, STD incidence rates, and the direct medical cost burden of STDs. In applying these methods to a hypothetical state, a reduction in annual funding of US $200,000 was estimated to lead to subsequent increases in STDs of 1.6% to 3.6%. Over 10 years, the reduction in funding totaled US $2.0 million, whereas the cumulative, additional direct medical costs of the increase in STDs totaled US $3.7 to US $8.4 million. The methods we proposed, though subject to important limitations, can allow STD prevention personnel to calculate evidence-based estimates of the effects of changes in their budget.

Indirect estimation of the prevalence of spinal muscular atrophy Type I, II, and III in the United States

BackgroundSpinal muscular atrophy (SMA) is a progressive, devastating disease and a leading inherited cause of infant mortality. The limited population-based literature is confined to small regional studies. Estimates of prevalence are needed to characterize the burden of SMA and to understand trends in prevalence by disease type as new treatments become available. The reported estimates of SMA genotype prevalence at birth consistently range from 8.5–10.3 per 100,000 live births, with a mid-range estimate of 9.4 per 100,000. Among infants born with an SMA genotype, it is reported that ~58% will develop SMA Type I, 29% will develop Type II, and 13% will develop Type III, respectively.ResultsUsing evidence from peer-reviewed literature for SMA birth prevalence, age at symptom onset, and SMA type-specific survival, and incorporating United States vital statistics, we constructed life tables to estimate prevalence for SMA Types I, II, and III in the United States. We estimated the number of prevalent cases in the US to be 8526, 9429, and 10,333 based on a birth prevalence of 8.5, 9.4, and 10.3, respectively (the lower, midpoint, and upper ends of the reported range). Assuming the midpoint of 9.4 and US-reported survival, the type-specific population prevalence estimates were 1610 for SMA Type I, 3944 for SMA Type II, and 3875 for SMA Type III. Evidence-based estimates of the number of people living with SMA in the United States in the published literature were previously unavailable.ConclusionsIn the absence of a survey or other means to directly estimate prevalence in the US population, estimates can be calculated indirectly using a life table.