Assessment of internal validity of prognostic models through bootstrapping and multiple imputation of missing data

Prognostic models have clinical appeal to aid therapeutic decision making. Two main practical challenges in development of such models are assessment of validity of models and imputation of missing data. In this study, importance of imputation of missing data and application of bootstrap technique in development, simplification, and assessment of internal validity of a prognostic model is highlighted. Overall, 310 breast cancer patients were recruited. Missing data were imputed 10 times. Then to deal with sensitivity of the model due to small changes in the data [internal validity], 100 bootstrap samples were drawn from each of 10 imputed data sets leading to 1000 samples. A Cox regression model was fitted to each of 1000 samples. Only variables retained in more than 50% of samples were used in development of final model. Four variables retained significant in more than 50% [i.e. 500 samples] of bootstrap samples; tumour size [91%], tumour grade [64%], history of benign breast disease [77%], and age at diagnosis [59%]. Tumour size was the strongest predictor with inclusion frequency exceeding 90%. Number of deliveries was correlated with age at diagnosis [r=0.35, P<0.001]. These two variables together retained significant in more than 90% of samples. We addressed two important methodological issues using a cohort of breast cancer patients. The algorithm combines multiple imputation of missing data and bootstrapping and has the potential to be applied in all kind of regression modelling exercises so as to address internal validity of models

effect of combined decongestive therapy and pneumatic compression pump on lymphedema indicators in patients with breast cancer related lymphedema

Lymphedema treatment is difficult and there is no consensus on the best treatment. This study evaluated the effect of combined decongestive therapy [CDT] and pneumatic compression pump on lymphedema indicators in patients with breast cancer related lymphedema [BCRL]. Twenty one women with BCRL were enrolled. The volume difference of upper limbs, the circumference at 9 areas and shoulder joint range of motion were measured in all patients. CDT was done by an educated nurse in two phases. In first phase, CDT was accompanied by use of a compression pump for 4 weeks, 3 days per week. In second phase, CDT was performed daily without compression pump for 4 weeks by patients at home. At the end of each phase, the same primary measurements were done for patients. The mean volume difference of the upper limbs and mean difference in circumference in all areas at different phases decreased significantly. Mean flexion, extension, abduction and external rotation [in degrees] at different phases increased significantly. CDT significantly reduced mean volume and mean circumference of the affected limb, and significantly increased shoulder joint range of motion. The findings support the optimal effects of CDT in the treatment of secondary lymphedema of upper extremity

Portal vein thrombosis: an unusual complication after laparoscopic cholecystectomy

Postoperative portal vein thrombosis is a rare complication which occurs most often after hepatobiliary surgery. To date, few cases following laparoscopic cholecystectomy have been reported. In this paper we present a case of portal vein thrombosis diagnosed with abdominal CT scan on the seventh day following laparoscopic cholecystectomy. The patient was administered therapeutic intravenous heparin with resolution of symptoms

Plasma selenium concentration and glutathione peroxidase activity in Breast Cancer patients before and after chemotherapy

The chemotherapeutic agents used for treatment of breast cancer are all shown to increase free oxygen radicals and generation of reactive oxygen species. The aim of this study was to evaluate effect of chemotherapy on plasma selenium [Se] concentration and glutathione peroxidase [GPX] activity in breast cancer patients. Seventeen women in stage II and III breast cancer were randomly selected from their population. Plasma Se was measured with Graphite furnace atomic absorption spectroscopy and GPX activity in erythrocyte by using spectrophotometric at baseline [before chemotherapy] and after chemotherapy. normally distributed data was expressed as mean +/- standard deviation. Statistical analysis was performed using Paired T-Test. Plasma Se concentration before and after chemotherapy was in normal range and no statistically difference was observed [156.23 +/- 25 micro g/L vs. 145.23 +/- 23 micro g/L respectively]. After chemotherapy, there was a significant [p < 0.05] higher erythrocyte GPX activity, as compared to initial activity at baseline. [22.28 +/- 4 U/grHb vs. 26.39 +/- 4 U/grHb respectively]. This study indicates that sufficient Se could increase GPX activity with have a protective effect against oxidative damages

clinicolaboratory scoring system for the management of acute appendicitis

Despite widespread imaging techniques which have significantly improved the management of acute appendicitis, cost-effective clinical decision-making concerning this condition is still a matter of debate. The aim of this study was to design a simple scoring system based on routine clinical and paraclinical data in patients suspected of having acute appendicitis. In this cross-sectional study, 402 consecutive patients, clinically suspected of having acute appendicitis and who were referred for general surgery consultation were evaluated. Nine common clinical and laboratory data including abdominal guarding, fever, shifting pain, leukocytosis, rebound tenderness, tenderness on rectal examination, vomiting, right lower quadrant tenderness and anorexia/nausea were recorded in each case and individually evaluated for sensitivity, specificity, positive predicted value and accuracy based on final outcome. A score of 3 was attributed to sign/symptoms with an accuracy of >/= 80%, 2 to sign/symptoms with an accuracy of 60-70%, and 1 to sign/symptoms with an accuracy of 50-70%. By selecting a cut-off point of more than 7 for operation and 6-7 for observation, the proposed scoring system decreased the negative appendectomy rate to 6.6% and observation rate to 3.5% as compared to 29% and 18% respectively, in conventional decision making. Applying this scoring system can improve clinical decision-making in acute appendicitis and effectively reduce negative appendectomy rates without increasing the rate of complications

Does oral metronidazole reduce complications in acute appendicitis?

In order to determine the effect of oral metronidazole [OM] in acute appendicitis, a prospective study was carried out in 305 adult patients [age: 15 - 50 yrs, mean: 25.5 yrs], randomly divided into a study group [SG] and a control group [CG]. In uncomplicated cases, the SG received OM 500 mg 2 hours pre-operatively and starting 5-6 hours post-operatively every eight hours for a total of three doses. The same dose schedule was continued for another three to five days in the SG if the appendicitis was complicated. A routine combination of penicillin, chloramphenicol and gentamicin was administered for the CG in complicated cases. No drug reaction was observed. The rate of wound infection was similar in both groups presenting with the same degree of pathology. There was no intra-abdominal collection. Length of hospitalization was one day shorter and hospital cost per day was 50% less in complicated cases in the SG as compared to the CG. In conclusion, OM is a safe and cost-effective drug that can be used both in simple and complicated appendicitis