Left-censored dementia incidences in estimating cohort effects.

We estimate the dementia incidence hazard in Germany for the birth cohorts 1900 until 1954 from a simple sample of Germany's largest health insurance company. Followed from 2004 to 2012, 36,000 uncensored dementia incidences are observed and further 200,000 right-censored insurants included. From a multiplicative hazard model we find a positive and linear trend in the dementia hazard over the cohorts. The main focus of the study is on 11,000 left-censored persons who have already suffered from the disease in 2004. After including the left-censored observations, the slope of the trend declines markedly due to Simpson's paradox, left-censored persons are imbalanced between the cohorts. When including left-censoring, the dementia hazard increases differently for different ages, we consider omitted covariates to be the reason. For the standard errors from large sample theory, left-censoring requires an adjustment to the conditional information matrix equality.

Weight reduction after an early version of the open gastric bypass for morbid obesity: results after 23 years.

BACKGROUND: While numerous promising short-term results of open gastric bypass for morbid obesity were published, the long-term outcome of earlier versions was somewhat disappointing. Thus, it was not until 1993 that this procedure was reintroduced with current modifications and now performed laparoscopically. Published long-term results of gastric bypass are still lacking. METHODS: Out of an original population of 195 patients, we retrospectively analyzed the outcome of 98 patients (82 women, 16 men, mean age 32 years [range 17-54], mean weight 132 kg [range 65-200], mean BMI 46.6 kg/m2) operated on in Erlangen with mean follow-up 22.9 years (range 16.5-25.4). 3 different bariatric operations were performed: horizontal gastroplasty (HGP, n=18), stapled Roux-en-Y gastric bypass (S-RYGBP, n=14) and transected Roux-en-Y gastric bypass (T-RYGBP, n=66). BMI and percentage of excess weight loss (%EWL) were calculated at time 0, and after 1, 2, 3, 10, 15, 20 and 25 years. RESULTS: Statistically significant weight loss was found for the whole patient population at every postoperative time-point compared to preoperative values. Maximal weight loss was achieved mainly during the first 3 years. However, initial and long-term outcome after HGP was significantly worse than after S-RYGBP or T-RYGBP. Gender did not significantly influence the results. CONCLUSION: Traditional open gastric bypass resulted in acceptable and safe long-term weight reduction. It may be assumed that laparoscopic gastric bypass with modern tiny pouch volumes based on the lesser curvature achieves even better and life-long weight reduction.

Prediction of lymph node metastasis in colorectal carcinoma by expressionof chemokine receptor CCR7.

Chemokine receptors are known to regulate homing of lymphocytes into secondary lymphoid organs and may also be involved in the lymphatic spread of solid tumors. Therefore, the assessment of chemokine receptor expression on colorectal carcinomas could potentially improve the prediction of lymph node spread. This is of great importance for the selection of patients for local therapy without the need for concomitant lymphatic dissection. Currently, only 5% of all patients can be selected for this desirable treatment option by established prognosticators. In a retrospective study, expression levels of the chemokine receptors CCR7, CXCR4 and CXCR5 were determined by immunohistochemistry on paraffin-embedded specimens of 99 colorectal carcinomas, which were curatively operated on, comprising all stages of the disease. Receptor expressions (absent vs. positive) from the overall tumor (OT) and from the invasion front (IF) including further prognosticators were correlated with lymph node status by uni- and multivariate analysis. Data were also correlated with synchronous distant metastases and overall survival. Median follow-up was 64 months. In univariate analysis, lymph node status correlated significantly with lymphovascular invasion, the expression of CCR7 IF, CCR7 OT, CXCR4 IF and CXCR4 OT, as well as pT category. Multivariate analysis revealed a significant correlation of lymph node status with lymphovascular invasion and CCR7 IF expression level. Most interestingly, CCR7 IF expression was significantly linked to decreased survival. CCR7 plays an important role in the mechanism of lymph node spread in colorectal carcinoma. Evaluation of the chemokine receptor expression profile seems to be appropriate to improve the selection of patients suited for local treatment and might constitute targets for nonsurgical therapy.