scholarly journals Title: “Using data on snus use in Sweden to compare different modelling approaches to estimate the population health impact of introducing a smoke-free tobacco product”

2019 ◽  
Author(s):  
Smilja Djurdjevic ◽  
Laszlo Pecze ◽  
Rolf Weitkunat ◽  
Frank Luedicke ◽  
John Fry ◽  
...  
Keyword(s):  
Smoking Prevalence ◽  
Transition Probabilities ◽  
Health Impact ◽  
European Countries ◽  
Sensitivity Analyses ◽  
Mortality Data ◽  
Published Data ◽  
Advantages And Disadvantages ◽  
Prevalence Estimates

Abstract Background We have developed an approach for modelling the health impact of introducing new smoke-free tobacco products. We wished to compare its estimates with those of alternative approaches, when applied to snus, used in Sweden for many years.Methods Modelling was restricted to men aged 30-79 years for 1980-2009 and to four smoking-related diseases. Mortality data were extracted for Sweden and other European countries. Published data provided Swedish prevalence estimates for combinations of never/former/current smoking and snus use, and smoking prevalence estimates for other European countries. Approach 1 compares mortality in Sweden and in other countries with a smoking prevalence similar to Sweden’s prevalence of combined smoking/snus use. Approaches 2 and 3 compare mortality in Sweden with hypothetical mortality had snus users smoked. Approach 3 uses our health impact model, individuals starting with the tobacco prevalence of Sweden in 1980. Tobacco histories during 30-year follow-up were then estimated using transition probabilities, with risk derived using a negative exponential model. Approach 2 uses annual tobacco prevalence estimates coupled with estimates of relative risk of current and former smokers regardless of history. The main applications of Approaches 2 and 3 assume that only smoking affects mortality, though sensitivity analyses using Approach 3 allow for risk to vary in snus users and dual users.Results Using Approach 2, estimated mortality increases in Sweden in 1980-2009 had snus not been introduced were: lung cancer 8,786; COPD 1,781; IHD 10,409; stroke 1,720. The main Approach 3 estimates were similar (7,931; 1,969; 12,501; 1,901). They decreased as risk in snus users and dual users increased. Approach 1 estimates differed wildly (77,762; 32,538; 77,438; 76,946), remaining very different following correction for differences between Sweden and the comparison countries in non-smoking-related disease mortality.Conclusions Approach 1 is unreliable, accounting inadequately for non-tobacco factors affecting mortality. Approaches 2 and 3 provide reasonably similar approximate estimates of the mortality increase had snus not been available, but have differing advantages and disadvantages. Only Approach 3 considers tobacco history, but develops histories using tobacco transition probabilities, which is possibly less reliable than using estimated tobacco prevalences at each follow-up year.

scholarly journals Using data on snus use in Sweden to compare different modelling approaches to estimate the population health impact of introducing a smoke-free tobacco product

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Smilja Djurdjevic ◽  
Laszlo Pecze ◽  
Rolf Weitkunat ◽  
Frank Luedicke ◽  
John Fry ◽  
...  
Keyword(s):  
Smoking Prevalence ◽  
Transition Probabilities ◽  
Health Impact ◽  
European Countries ◽  
Sensitivity Analyses ◽  
Mortality Data ◽  
Published Data ◽  
Advantages And Disadvantages ◽  
Prevalence Estimates

Abstract Background We have developed an approach for modelling the health impact of introducing new smoke-free tobacco products. We wished to compare its estimates with those of alternative approaches, when applied to snus, used in Sweden for many years. Methods Modelling was restricted to men aged 30–79 years for 1980–2009 and to four smoking-related diseases. Mortality data were extracted for Sweden and other European countries. Published data provided Swedish prevalence estimates for combinations of never/former/current smoking and snus use, and smoking prevalence estimates for other European countries. Approach 1 compares mortality in Sweden and in other countries with a smoking prevalence similar to Sweden’s prevalence of combined smoking/snus use. Approaches 2 and 3 compare mortality in Sweden with hypothetical mortality had snus users smoked. Approach 3 uses our health impact model, individuals starting with the tobacco prevalence of Sweden in 1980. Tobacco histories during 30-year follow-up were then estimated using transition probabilities, with risk derived using a negative exponential model. Approach 2 uses annual tobacco prevalence estimates coupled with estimates of relative risk of current and former smokers regardless of history. The main applications of Approaches 2 and 3 assume that only smoking affects mortality, though sensitivity analyses using Approach 3 allow for risk to vary in snus users and dual users. Results Using Approach 2, estimated mortality increases in Sweden in 1980–2009 had snus not been introduced were: lung cancer 8786; COPD 1781; IHD 10,409; stroke 1720. The main Approach 3 estimates were similar (7931, 1969; 12,501; 1901). They decreased as risk in snus users and dual users increased. Approach 1 estimates differed wildly (77,762, 32,538; 77,438; 76,946), remaining very different following correction for differences between Sweden and the comparison countries in non-smoking-related disease mortality. Conclusions Approach 1 is unreliable, accounting inadequately for non-tobacco factors affecting mortality. Approaches 2 and 3 provide reasonably similar approximate estimates of the mortality increase had snus not been available, but have differing advantages and disadvantages. Only Approach 3 considers tobacco history, but develops histories using tobacco transition probabilities, which is possibly less reliable than using estimated tobacco prevalences at each follow-up year.

scholarly journals Using data on snus use in Sweden to compare different modelling approaches to estimate the population health impact of introducing a smoke-free tobacco product

2019 ◽  
Author(s):  
Peter Lee ◽  
Smilja Djurdjevic ◽  
Laszlo Pecze ◽  
Rolf Weitkunat ◽  
Frank Luedicke ◽  
...  
Keyword(s):  
Smoking Prevalence ◽  
Transition Probabilities ◽  
Health Impact ◽  
European Countries ◽  
Sensitivity Analyses ◽  
Mortality Data ◽  
Published Data ◽  
Advantages And Disadvantages ◽  
Prevalence Estimates

Abstract Background We have developed an approach for modelling the health impact of introducing new smoke-free tobacco products. We wished to compare its estimates with those of alternative approaches, when applied to snus, used in Sweden for many years. Methods Modelling was restricted to men aged 30-79 years for 1980-2009 and to four smoking-related diseases. Mortality data were extracted for Sweden and other European countries. Published data provided Swedish prevalence estimates for combinations of never/former/current smoking and snus use, and smoking prevalence estimates for other European countries. Approach 1 compares mortality in Sweden and in other countries with a smoking prevalence similar to Sweden’s prevalence of combined smoking/snus use. Approaches 2 and 3 compare mortality in Sweden with hypothetical mortality had snus users smoked. Approach 3 uses our health impact model, individuals starting with the tobacco prevalence of Sweden in 1980. Tobacco histories during 30-year follow-up were then estimated using transition probabilities, with risk derived using a negative exponential model. Approach 2 uses annual tobacco prevalence estimates coupled with estimates of relative risk of current and former smokers regardless of history. The main applications of Approaches 2 and 3 assume that only smoking affects mortality, though sensitivity analyses using Approach 3 allow for risk to vary in snus users and dual users. Results Using Approach 2, estimated mortality increases in Sweden in 1980-2009 had snus not been introduced were: lung cancer 8,786; COPD 1,781; IHD 10,409; stroke 1,720. The main Approach 3 estimates were similar (7,931; 1,969; 12,501; 1,901). They decreased as risk in snus users and dual users increased. Approach 1 estimates differed wildly (77,762; 32,538; 77,438; 76,946), remaining very different following correction for differences between Sweden and the comparison countries in non-smoking-related disease mortality. Conclusions Approach 1 is unreliable, accounting inadequately for non-tobacco factors affecting mortality. Approaches 2 and 3 provide reasonably similar approximate estimates of the mortality increase had snus not been available, but have differing advantages and disadvantages. Only Approach 3 considers tobacco history, but develops histories using tobacco transition probabilities, which is possibly less reliable than using estimated tobacco prevalences at each follow-up year.

scholarly journals Title: “Using data on snus use in Sweden to compare different modelling approaches to estimate the population health impact of introducing a smoke-free tobacco product”

2019 ◽  
Author(s):  
Smilja Djurdjevic ◽  
Laszlo Pecze ◽  
Rolf Weitkunat ◽  
Frank Luedicke ◽  
John Fry ◽  
...  
Keyword(s):  
Smoking Prevalence ◽  
Transition Probabilities ◽  
Health Impact ◽  
European Countries ◽  
Sensitivity Analyses ◽  
Mortality Data ◽  
Published Data ◽  
Advantages And Disadvantages ◽  
Prevalence Estimates

Abstract Background We have developed an approach for modelling the health impact of introducing new smoke-free tobacco products. We wished to compare its estimates with those of alternative approaches, when applied to snus, used in Sweden for many years.Methods Modelling was restricted to men aged 30-79 years for 1980-2009 and to four smoking-related diseases. Mortality data were extracted for Sweden and other European countries. Published data provided Swedish prevalence estimates for combinations of never/former/current smoking and snus use, and smoking prevalence estimates for other European countries. Approach 1 compares mortality in Sweden and in other countries with a smoking prevalence similar to Sweden’s prevalence of combined smoking/snus use. Approaches 2 and 3 compare mortality in Sweden with hypothetical mortality had snus users smoked. Approach 3 uses our health impact model, individuals starting with the tobacco prevalence of Sweden in 1980. Tobacco histories during 30-year follow-up were then estimated using transition probabilities, with risk derived using a negative exponential model. Approach 2 uses annual tobacco prevalence estimates coupled with estimates of relative risk of current and former smokers regardless of history. The main applications of Approaches 2 and 3 assume that only smoking affects mortality, though sensitivity analyses using Approach 3 allow for risk to vary in snus users and dual users.Results Using Approach 2, estimated mortality increases in Sweden in 1980-2009 had snus not been introduced were: lung cancer 8,786; COPD 1,781; IHD 10,409; stroke 1,720. The main Approach 3 estimates were similar (7,931; 1,969; 12,501; 1,901). They decreased as risk in snus users and dual users increased. Approach 1 estimates differed wildly (77,762; 32,538; 77,438; 76,946), remaining very different following correction for differences between Sweden and the comparison countries in non-smoking-related disease mortality.Conclusions Approach 1 is unreliable, accounting inadequately for non-tobacco factors affecting mortality. Approaches 2 and 3 provide reasonably similar approximate estimates of the mortality increase had snus not been available, but have differing advantages and disadvantages. Only Approach 3 considers tobacco history, but develops histories using tobacco transition probabilities, which is possibly less reliable than using estimated tobacco prevalences at each follow-up year.

scholarly journals Spatiotemporal Econometrics Models for Old Age Mortality in Europe

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1061
Author(s):  
Patricia Carracedo ◽  
Ana Debón
Keyword(s):  
Panel Data ◽  
Goodness Of Fit ◽  
Population Aging ◽  
European Population ◽  
Data Models ◽  
European Countries ◽  
Mortality Data ◽  
Panel Data Models ◽  
Estimation Of Parameters ◽  
Advantages And Disadvantages

In the past decade, panel data models using time-series observations of several geographical units have become popular due to the availability of software able to implement them. The aim of this study is an updated comparison of estimation techniques between the implementations of spatiotemporal panel data models across MATLAB and R softwares in order to fit real mortality data. The case study used concerns the male and female mortality of the aged population of European countries. Mortality is quantified with the Comparative Mortality Figure, which is the most suitable statistic for comparing mortality by sex over space when detailed specific mortality is available for each studied population. The spatial dependence between the 26 European countries and their neighbors during 1995–2012 was confirmed through the Global Moran Index and the spatiotemporal panel data models. For this reason, it can be said that mortality in European population aging not only depends on differences in the health systems, which are subject to national discretion but also on supra-national developments. Finally, we conclude that although both programs seem similar, there are some differences in the estimation of parameters and goodness of fit measures being more reliable MATLAB. These differences have been justified by detailing the advantages and disadvantages of using each of them.

Estimating the Public Health Impact from Introducing Tobacco-Free Nicotine Pouches Into the US

2021 ◽  
Author(s):  
Peter N Lee ◽  
John S Fry ◽  
Tryggve Ljung
Keyword(s):  
Smoking Status ◽  
Health Impact ◽  
Sensitivity Analyses ◽  
Base Case ◽  
Initiation Rate ◽  
Individual Parameter ◽  
Product Use ◽  
The Us ◽  
Current Product

Abstract BackgroundFor smokers not intending to quit, switching to a reduced-risk nicotine product should be healthier than continuing smoking. We estimate the health impact, over the period 2000-2050, of introducing into the US the nicotine pouch ZYN. ZYN’s toxicant profile and method of use is like that for Swedish snus, a product with known health effects much less than smoking. MethodsOur modelling approach is similar to others developed for estimating potential effects of new tobacco products. It starts with a simulated cohort of 100,000 individuals in the year 2000 subdivided by age, sex, and smoking status (including years since quitting). They are followed annually accounting for births, net immigrations, deaths and product use changes, with follow-up carried out in the Base Case (ZYN not introduced) and Modified Case (ZYN introduced). Using informed assumptions about initiation, quitting and switching rates, distributions of the population over time are then constructed for each Case, which are used to estimate product-related mortality based on assumptions about the relative risk according to product use. ResultsWhereas in both Base and Modified Cases, the prevalence of any current product use is predicted to decline from about 22% to 10% during follow-up, in the Modified Case about 25% of current users use ZYN by 2050, about a quarter being dual users and the rest ZYN-only users. Over the 50 years, deaths at ages 35-84 from product use among the 100,000 are estimated as 249 less in the Modified than the Base Case, equivalent to about 700,000 less deaths in the whole US. Sensitivity analyses varying individual parameter values confirm the benefits of switching to ZYN, which increase as either the switching rate to ZYN increases or the initiation rate of ZYN relative to smoking increases. Even assuming the reduction in excess mortality risk using ZYN use is 20% of that from smoking rather than the 3.5% assumed in the main analyses, the reduction in product-related deaths would still be 213, or about 600,000 in the US. ConclusionsAlthough such model-based estimates are subject to uncertainties, the results suggest that introducing ZYN could substantially reduce smoking-attributable deaths.

scholarly journals A Computational Model for Assessing the Population Health Impact of Introducing a Modified Risk Claim on an Existing Smokeless Tobacco Product

2019 ◽  
Vol 16 (7) ◽  
pp. 1264 ◽  
Author(s):  
Raheema Muhammad-Kah ◽  
Yezdi Pithawalla ◽  
Edward Boone ◽  
Lai Wei ◽  
Michael Jones ◽  
...  
Keyword(s):  
Smokeless Tobacco ◽  
Computational Models ◽  
Transition Probabilities ◽  
Health Impact ◽  
Tobacco Product ◽  
Sensitivity Analyses ◽  
Relative Risk Ratio ◽  
Base Case ◽  
Net Benefit ◽  
Premature Deaths

Computational models are valuable tools for predicting the population effects prior to Food and Drug Administration (FDA) authorization of a modified risk claim on a tobacco product. We have developed and validated a population model using best modeling practices. Our model consists of a Markov compartmental model based on cohorts starting at a defined age and followed up to a specific age accounting for 29 tobacco-use states based on a cohort members transition pathway. The Markov model is coupled with statistical mortality models and excess relative risk ratio estimates to determine survival probabilities from use of smokeless tobacco. Our model estimates the difference in premature deaths prevented by comparing Base Case (“world-as-is”) and Modified Case (the most likely outcome given that a modified risk claim is authorized) scenarios. Nationally representative transition probabilities were used for the Base Case. Probabilities of key transitions for the Modified Case were estimated based on a behavioral intentions study in users and nonusers. Our model predicts an estimated 93,000 premature deaths would be avoided over a 60-year period upon authorization of a modified risk claim. Our sensitivity analyses using various reasonable ranges of input parameters do not indicate any scenario under which the net benefit could be offset entirely.

scholarly journals Plasma 25-Hydroxyvitamin D Concentrations Are Inversely Associated with All-Cause Mortality among a Prospective Cohort of Chinese Adults Aged ≥80 Years

2019 ◽  
Vol 149 (6) ◽  
pp. 1056-1064 ◽  
Author(s):  
Chen Mao ◽  
Fu-Rong Li ◽  
Zhao-Xue Yin ◽  
Yue-Bin Lv ◽  
Jie-Si Luo ◽  
...  
Keyword(s):  
Vitamin D ◽  
Prospective Cohort ◽  
Sensitivity Analyses ◽  
Mortality Data ◽  
Inverse Association ◽  
Chinese Adults ◽  
Hydroxyvitamin D ◽  
All Cause Mortality ◽  
25 Hydroxyvitamin D

ABSTRACT Background High concentrations of plasma 25-hydroxyvitamin D [25(OH)D], a marker of circulating vitamin D, have been associated with a lower risk of mortality in epidemiologic studies of multiple populations, but the association for Chinese adults aged ≥80 y (oldest old) remains unclear. Objective We investigated the association between plasma [25(OH)D] concentration and all-cause mortality among Chinese adults aged ≥80 y. Design The present study is a prospective cohort study of 2185 Chinese older adults (median age: 93 y). Prospective all-cause mortality data were analyzed for survival in relation to plasma 25(OH)D using Cox proportional hazards regression models, with adjustments for potential sociodemographic and lifestyle confounders and biomarkers. The associations were measured with HR and 95% CIs. Results The median plasma 25(OH)D concentration was 34.4 nmol/L at baseline. Over the 5466 person-year follow-up period, 1100 deaths were identified. Men and women were analyzed together as no effect modification by sex was found. After adjusting for multiple potential confounders, the risk of all-cause mortality decreased as the plasma 25(OH)D concentration increased (P-trend <0.01). Compared with the lowest age-specific quartile of plasma 25(OH)D, the adjusted HRs for mortality for the second, third, and fourth age-specific quartiles were 0.72 (95% CI: 0.57, 0.90), 0.73 (95% CI: 0.58, 0.93), and 0.61 (95% CI: 0.47, 0.81), respectively. The observed associations were broadly consistent across age and other subgroups. Sensitivity analyses generated similar results after excluding participants who died within 2 y of follow-up or after further adjustment for ethnicity and chronic diseases. Conclusions A higher plasma 25-hydroxyvitamin D concentration was associated with a reduced risk of all-cause mortality among Chinese adults aged ≥80 y. This observed inverse association warrants further investigation in randomized controlled trials testing vitamin D supplementation in this age group.

scholarly journals Transitions in Smoking among Adults Newly Purchasing the JUUL System

2021 ◽  
Vol 45 (3) ◽  
pp. 546-562
Author(s):  
Shivaani Prakash ◽  
Yingying Xu ◽  
Nicholas I. Goldenson ◽  
Rasmus Wissmann ◽  
Robyn Gougelet ◽  
...  
Keyword(s):  
Smoking Prevalence ◽  
Smoking Status ◽  
Health Impact ◽  
Adult Age ◽  
Sample Composition ◽  
Former Smokers ◽  
Never Smokers ◽  
One Year ◽  
First Time

Objectives: In this study, we prospectively assessed changes in smoking a year after US adults' first-time purchase of a JUUL Starter Kit (JSK). Methods: Descriptive analyses assessed transitions in smoking status at 12 months among adult (age ≥21) JSK purchasers providing baseline and 12-month follow-up data (N = 27,164 [49.0% of baseline]), stratified by baseline smoking status. Baseline regular use of other ENDS was also considered. Results: Purchasers included baseline past 30-day smokers (65.2%), former smokers (12.0%), and never smokers (9.7%); over 90% were ever-smokers. One year later, the majority (58%) of those smoking at baseline reported no longer smoking. Former smokers or never smokers who were smoking at 12 months represented less than 2% of respondents. Former and current smokers who were regularly using other ENDS at baseline were less likely to report smoking at 12 months. Conclusions: Past 30-day smoking prevalence in a large longitudinal study of first-time JSK purchasers fell by more than half over 12 months. Analyzing the sample composition at purchase and transitions within subgroups defined by smoking status allows for a detailed understanding to help inform assessments of the population health impact of ENDS.

Cost-Utility Of Bortezomib In Induction Treatment Prior To Autologous Stem-Cell Transplantation (ASCT) In Previously Untreated Multiple Myeloma Patients In Canada

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1735-1735 ◽  
Author(s):  
Tom Kouroukis ◽  
Darrell White ◽  
Morgan Kruse ◽  
Donna Lawrence ◽  
Cristina Trambitas ◽  
...  
Keyword(s):  
Transition Probabilities ◽  
Cost Effective ◽  
Cost Utility ◽  
Sensitivity Analyses ◽  
Induction Treatment ◽  
Health State ◽  
Health States ◽  
Induction Regimen ◽  
The Cost

Abstract Introduction The effectiveness of bortezomib for induction treatment prior to ASCT in multiple myeloma (MM) patients has been demonstrated in a number of randomized, open-label phase III trials, including the IFM 2005-01 trial (Harousseau et al., J Clin Oncol 2010;28(30):4621-9). This trial showed that the addition of bortezomib as part of an induction treatment prior to ASCT resulted in statistically significant improvements in post-induction response rates and longer progression-free survival (PFS) compared to a non-bortezomib containing regimen (NBCR). The objective of this study was to assess the cost-utility of a bortezomib-containing regimen (BCR) vs. a NBCR for induction treatment in previously untreated MM patients prior to ASCT from a Canadian public payer perspective, based on the results of the IFM 2005-01 study. Methods A Markov model was developed to estimate the cost-utility over a lifetime horizon (50 years) in previously untreated MM patients undergoing induction and ASCT. The model simulated disease progression of patients with previously untreated MM through three health states: “progression-free”, “progression” and “death”, with all patients beginning in the progression-free state. The PFS and overall survival (OS) curves from the IFM 2005-01 trial were extrapolated beyond the study follow-up period to estimate the timeframe spent in each health state. Each health state was associated with a utility value and direct medical costs. Utilities for the progression-free and progression health states were derived from a previous cost-utility analysis for bortezomib and were 0.81 and 0.645, respectively (Hornberger et al., Eur J Haematol 2010;85(6):484-91). Transition probabilities between health states were estimated by calibrating the model to the PFS and OS curves from the IFM 2005-01 trial. In the base case, transition probabilities beyond the trial follow-up period were conservatively assumed to be equal for both treatment groups. Medical resource utilization was estimated using the IFM 2005-01 trial, and supplemented by published literature and clinical advisors. Clinical advisors also provided input on management of adverse events (> grade 3) and treatment of patients who progressed after induction and ASCT. Resource costs were estimated using Canadian sources ($CAN 2012) and costs and outcomes were discounted at 5% annually. Because patients in each group incurred similar costs (i.e. cost of an ASCT), only incremental costs between the two arms were included in the analysis. One-way sensitivity analyses and probabilistic sensitivity analyses were performed to test the robustness of the model. Results The mean total MM-related cost over the lifetime analysis in the model was $68,800 per patient treated with a BCR and $47,000 per patient treated with a NBCR. Addition of bortezomib to the induction regimen increased costs by $21,700 (see table). Over the model lifetime, a delay in progression with a BCR led to 0.25 years of additional survival compared to a NBCR and a quality-adjusted life-year (QALY) gain of 0.22 years. The incremental cost-utility ratio for induction using a BCR compared to a NBCR approach was $99,200/QALY. Sensitivity analyses identified the major factors impacting the cost-utility ratio as: transition probabilities beyond the trial follow-up period, discounting, utilities and bortezomib costs. The probability of a BCR being cost-effective compared to a NBCR was 43.9% at a threshold of $100,000/QALY. Conclusions A number of phase 3 trials have demonstrated the effectiveness of bortezomib as part of an induction regimen prior to ASCT. This analysis indicates that, from a Canadian perspective, induction treatment with a BCR in previously untreated MM patients prior to ASCT can be cost-effective at conventional decision thresholds with a cost-utility ratio of $99,200/QALY. Disclosures: Kouroukis: Janssen Inc.: Honoraria. White:Janssen Inc.: Consultancy, Honoraria. Kruse:OptumInsight: Employment. Lawrence:OptumInsight: Employment. Trambitas:Janssen Inc.: Employment.

Patients with “benign” Chiari I malformations require surgical decompression at a low rate

2019 ◽  
Vol 23 (4) ◽  
pp. 498-506 ◽  
Author(s):  
Tofey J. Leon ◽  
Elizabeth N. Kuhn ◽  
Anastasia A. Arynchyna ◽  
Burkely P. Smith ◽  
R. Shane Tubbs ◽  
...  
Keyword(s):  
Surgical Treatment ◽  
Posterior Fossa ◽  
Multivariate Logistic Regression Analysis ◽  
Large Cohort ◽  
Initial Evaluation ◽  
Published Data ◽  
Posterior Fossa Decompression ◽  
Signal Abnormality ◽  
Chiari I

OBJECTIVEThere are sparse published data on the natural history of “benign” Chiari I malformation (CM-I)—i.e., Chiari with minimal or no symptoms at presentation and no imaging evidence of syrinx, hydrocephalus, or spinal cord signal abnormality. The purpose of this study was to review a large cohort of children with benign CM-I and to determine whether these children become symptomatic and require surgical treatment.METHODSPatients were identified from institutional outpatient records using International Classification of Diseases, 9th Revision, diagnosis codes for CM-I from 1996 to 2016. After review of the medical records, patients were excluded if they 1) did not have a diagnosis of CM-I, 2) were not evaluated by a neurosurgeon, 3) had previously undergone posterior fossa decompression, or 4) had imaging evidence of syringomyelia at their first appointment. To include only patients with benign Chiari (without syrinx or classic Chiari symptoms that could prompt immediate intervention), any patient who underwent decompression within 9 months of initial evaluation was excluded. After a detailed chart review, patients were excluded if they had classical Chiari malformation symptoms at presentation. The authors then determined what changes in the clinical picture prompted surgical treatment. Patients were excluded from the multivariate logistic regression analysis if they had missing data such as race and insurance; however, these patients were included in the overall survival analysis.RESULTSA total of 427 patients were included for analysis with a median follow-up duration of 25.5 months (range 0.17–179.1 months) after initial evaluation. Fifteen patients had surgery at a median time of 21.0 months (range 11.3–139.3 months) after initial evaluation. The most common indications for surgery were tussive headache in 5 (33.3%), syringomyelia in 5 (33.3%), and nontussive headache in 5 (33.3%). Using the Kaplan-Meier method, rate of freedom from posterior fossa decompression was 95.8%, 94.1%, and 93.1% at 3, 5, and 10 years, respectively.CONCLUSIONSAmong a large cohort of patients with benign CM-I, progression of imaging abnormalities or symptoms that warrant surgical treatment is infrequent. Therefore, these patients should be managed conservatively. However, clinical follow-up of such individuals is justified, as there is a low, but nonzero, rate of new symptom or syringomyelia development. Future analyses will determine whether imaging or clinical features present at initial evaluation are associated with progression and future need for treatment.

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