Mohsen Sadatsafavi

Clinical course of ulcerative colitis in patients with and without primary sclerosing cholangitis

Background and Aim: We noticed in our practice that patients with ulcerative colitis (UC) who have developed primary sclerosing cholangitis (PSC) experience a milder course of colonic disease. Our objective in this study was to define whether or not there is any difference between UC activity and its course in patients with and without PSC.

Discordance in diagnosis of osteoporosis using spine and hip bone densitometry

BackgroundDiagnostic discordance for osteoporosis is the observation that the T-score of an individual patient varies from one key measurement site to another, falling into two different diagnostic categories identified by the World Health Organization (WHO) classification system. This study was conducted to evaluate the presence and risk factors for this phenomenon in a large sample of Iranian population.MethodsDemographic data, anthropometric measurements, and risk factors for osteoporosis were derived from a database on 4229 patients referred to a community-based outpatient osteoporosis testing center from 2000 to 2003. Dual-energy X-ray absorptiometry (DXA) was performed on L1–L4 lumbar spine and total hip for all cases. Minor discordance was defined as present when the difference between two sites was no more than one WHO diagnostic class. Major discordance was present when one site is osteoporotic and the other is normal. Subjects with incomplete data were excluded.ResultsIn 4188 participants (3848 female, mean age 53.4 ± 11.8 years), major discordance, minor discordance, and concordance of T-scores were seen in 2.7%, 38.9% and 58.3%, respectively. In multivariate logistic regression analysis, older age, menopause, obesity, and belated menopause were recognized as risk factors and hormone replacement therapy as a protective factor against T-score discordance.ConclusionThe high prevalence of T-score discordance may lead to problems in interpretation of the densitometry results for some patients. This phenomenon should be regarded as a real and prevalent finding and physicians should develop a particular strategy approaching to these patients.

Frequency of myasthenic crisis in relation to thymectomy in generalized myasthenia gravis: A 17-year experience

BackgroundMyasthenic crisis is the most serious life-threatening event in generalized myasthenia gravis (MG) patients. The objective of this study was to assess the long-term impact of thymectomy on rate and severity of these attacks in Iranian patients.MethodsWe reviewed the clinical records from 272 myasthenic patients diagnosed and treated in our neurology clinic during 1985 to 2002. Fifty-three patients were excluded because of unconfirmed diagnosis, ocular form of MG, contraindication to surgery, concomitant diseases and loss to follow-up. The Osserman classification was used to assess the initial severity of the disease. Frequency and severity of the attacks were compared between two groups with appropriate statistical tests according to the nature of variables. Multivariate logistic regression analysis was used to assess the predictors of myasthenic crisis in the group of patients without thymoma.Results110 patients were in thymectomy group and the other 109 patients were on medical therapy. These two groups had no significant differences with respect to age at onset, gender, Osserman score in baseline and follow up period. 62 patients (28.3% of all 219 patients) had reported 89 attacks of myasthenic crisis. 20 patients of 62 (32%) were in thymectomy group and 42 (68%) were in the other group. There was significant difference between the two groups in number of patients with crisis (P = 0.001; odds ratio = 2.8 with 95% CI of 1.5 to 5.2). In addition, these attacks were more severe in group of non-thymectomized patients as the duration of ICU admission was longer and they needed more ventilatory support during their attacks. Regression model showed thymectomy and lower age at onset as two predictors of decrement in myasthenic crisis rate in non-thymomatous MG patients.ConclusionsIt is suggested that frequency and severity of myasthenic attacks as important endpoints in evaluation of MG patients. Thymectomy seems to have a preventive role on rate and severity of these attacks.

Costs and Health Outcomes Associated With Primary vs Secondary Care After an Asthma-Related Hospitalization: A Population-Based Study

BACKGROUNDnPatients with a history of asthma-related hospitalizations are at high risk of readmission and generally consume a large amount of health-care resources. It is not clear if the secondary care provided by specialists after an episode of asthma-related hospitalization is associated with better outcomes compared with the primary care provided by general practitioners.nnnMETHODSnUsing population-based administrative health data from the province of British Columbia, Canada, we created a propensity-score-matched cohort of individuals who received primary vs secondary care in the 60 days after discharge from asthma-related hospitalization. Total direct asthma-related medical costs (primary outcome) and health service use and measures of medication adherence (secondary outcomes) were compared for the next 12 months.nnnRESULTSnTwo thousand eighty-eight individuals were equally matched between the primary and secondary care groups. There was no difference in the direct asthma-related costs (difference

Heteroscedastic Regression Analysis of Factors Affecting BMD Monitoring

567; 95% CI, -

Optimal decision criterion for detecting change in bone mineral density during serial monitoring: A Bayesian approach

276 to

Artificial neural networks in prediction of bone density among post-menopausal women.

1,410) and rate of readmission (rate ratio [RR] = 1.06; 95% CI, 0.85-1.32) between the secondary and the primary care groups. Patients under secondary care had a higher rate of asthma-related outpatient service use (RR = 1.22; 95% CI, 1.11-1.35) but a lower rate of short-acting β-agonist dispensation (RR = 0.91; 95% CI, 0.85-0.98). The proportion of days covered with a controller medication was higher among the secondary care group (difference of 3.2%; 95% CI, 0.4%-6.0%).nnnCONCLUSIONSnCompared with those who received only primary care, patients who received secondary care showed evidence of more appropriate treatment. Nevertheless, there were no differences in the costs or the risk of readmission. Adherence to asthma medication in both groups was poor, indicating the need for raising the quality of care provided by generalists and specialists alike.

Outcome predictors in nonoperative management of newly diagnosed subacromial impingement syndrome: a longitudinal study.

Identifying factors affecting BMD precision and interindividual heterogeneity in BMD change can help optimize BMD monitoring. BMD change for the lumbar spine and total hip for short‐term reproducibility (n = 328) and long‐term clinical monitoring (n = 2720) populations were analyzed with heteroscedastic regression using linear prediction for mean (monitoring population only) and log‐linear prediction for SD (both populations). For clinical monitoring, male sex, baseline body mass index (BMI), and systemic corticosteroid use were associated with greater SD of BMD change. Weight gain was negatively associated with SD for the hip, whereas height change was positively associated with SD for the spine. Each additional year of monitoring increased the SD by 6.5–9.2%. Osteoporosis treatment affected mean change but did not increase dispersion. For short‐term reproducibility, performing scans on a different day increased the SD of measurement error by 38–44%. Baseline BMD, difference in bone area, and a repeat scan performed by different technologists were associated with higher measurement error only for the hip. For both samples, heteroscedastic regression outperformed models that assumed homogeneous variance. Heteroscedastic regression techniques are powerful yet underused tools in analyzing longitudinal BMD data and can be used to generate individualized predictions of BMD change and measurement error.

Eff ects of a mobile phone short message service on antiretroviral treatment adherence in Kenya (WelTel Kenya1): a randomised trial

SummaryInterpretation of change in serial bone densitometry using least significant change (LSC) may not lead to optimal decision making. Using the principles of Bayesian statistics and decision sciences, we developed the Optimal Decision Criterion (ODC) which resulted in 11–12.5% higher rate of correct classification compared with the LSC method.IntroductionThe interpretation of change in serial bone densitometry emphasizes using least significant change (LSC) to distinguish between true changes and measurement error.MethodsUsing the principles of Bayesian statistics and decision sciences, we developed the optimal decision criterion (ODC) based on maximizing a ‘utility’ function that rewards the correct and penalizes the incorrect classification of change. The relationship between LSC and ODC is demonstrated using a clinical sample from the Manitoba Bone Density Program.ResultsUnder certain conditions, it can be shown that using LSC at the 95% confidence level implicitly equates the benefit of 39 true positive diagnoses with the harm of one false positive classification of BMD change. ODC resulted in an 11% higher rate of correct classification for lumbar spine BMD change and a 12.5% better performance for classifying total hip BMD change compared with LSC with this method.ConclusionsODC has the same clinical interpretation as LSC but with two major advantages: it can incorporate prior knowledge of the likely values of the true change and it can be fine-tuned based on the relative value placed on the correct and incorrect classifications. Bayesian statistics and decision sciences could potentially increase the yield of a BMD monitoring program.

Preferred skeletal site for osteoporosis screening in high-risk populations

Artificial neural networks (ANN) are promising tools in learning complex interplay of factors on a particular outcome. We performed this study to compare the predictive power of ANN and conventional methods in prediction of bone mineral density (BMD) in Iranian post-menopausal women. A database of 10 input variables from 2158 participants was randomly divided into training (1400), validation (150) and test (608) groups. Multivariate linear regression and ANN models were developed and validated on the training, and validation sets and outcomes (femoral neck and lumbar T-scores) were predicted and compared on the test group using different numbers of input variables. Results were evaluated by comparing the mean square of differences between predicted and reference values (non-central chi-square test) and by measuring area under the receiver operating characteristic curve (AUROC) around cut-off value of −2.5 for T-scores. For models with less than 3 input variables in femoral neck and 4 variables in spinal column, performance of regression and ANN models was almost the same. As more variables imported into models, ANN outperformed linear regression models. AUROC varied in 2 to 10 variable models as follows: for ANN in spine, from 0.709 to 0.774; linear models in spine, from 0.709 to 0.744; ANN in femoral neck, from 0.801 to 0.867; linear models in femoral neck, from 0.799 to 0.834. The ANN model performed better than five established patient selection tools in the test group. Superior performance of neural networks than linear models demonstrate their advantage especially in mass screening applications, when even a slight enhancement in performance results in significant decrease in number of misclassifications.