Development of a multi-parametric model predictive control algorithm for insulin delivery in type 1 diabetes mellitus using clinical parameters.

A multi-parametric model predictive control (mpMPC) algorithm for subcutaneous insulin delivery for individuals with type 1 diabetes mellitus (T1DM) that is computationally efficient, robust to variations in insulin sensitivity, and involves minimal burden for the user is proposed. System identification was achieved through impulse response tests feasible for ambulatory conditions on the UVa/Padova simulator adult subjects with T1DM. An alternative means of system identification using readily available clinical parameters was also investigated. A safety constraint was included explicitly in the algorithm formulation using clinical parameters typical of those available to an attending physician. Closed-loop simulations were carried out with daily consumption of 200 g carbohydrate. Controller robustness was assessed by subject/model mismatch scenarios addressing daily, simultaneous variation in insulin sensitivity and meal size with the addition of Gaussian white noise with a standard deviation of 10%. A second-order-plus-time-delay transfer function model fit the validation data with a mean (coefficient of variation) root-mean-square-error (RMSE) of 26 mg/dL (19%) for a 3 h prediction horizon. The resulting control law maintained a low risk Low Blood Glucose Index without any information about carbohydrate consumption for 90% of the subjects. Low-order linear models with clinically meaningful parameters thus provided sufficient information for a model predictive control algorithm to control glycemia. The use of clinical knowledge as a safety constraint can reduce hypoglycemic events, and this same knowledge can further improve glycemic control when used explicitly as the controller model. The resulting mpMPC algorithm was sufficiently compact to be implemented on a simple electronic device.

Convulsions induced by metronidazole treatment for Clostridium difficile-associated disease in chronic renal failure.

Clostridium difficile-related diarrhea and colitis are common health problems, especially in elderly, frail hospitalized patients. The drug of choice is metronidazole, which can be associated, in long or high doses, with neurotoxic side effects. We report convulsions induced by short-term metronidazole therapy used in conventional doses for Clostridium difficile colitis in an elderly patient with chronic renal failure.

The prehospitalization functional and cognitive status and the course of acute infectious disease in the elderly.

A total of 105 elderly patients hospitalized for acute infectious disease were classified into prehospital demented and non demented groups and into dependent and independent groups. Demographic data, clinical and biological parameters and previous health problems were recorded. There was a significant difference between the two cognitive and functional groups in complications, length of stay, dehydration, confusion, albumin and hemoglobin. A logistic regression analysis taking into account the epidemiologic parameters, functional and cognitive status and the medical health problems has shown that only age, dementia and previous neurologic disease (mainly stroke) are independent risk factors for confusion and complications. Thus, the prehospitalization function, cognitive status and previous neurologic disease in elderly patients with acute infections may have a predictive and prognostic value.

Prevalence and survival of myelodysplastic syndrome of the refractory anemia type in hospitalized cognitively different geriatric patients.

BACKGROUND: Myelodysplastic syndrome (MDS) is predominantly a disease of old age. The number of MDS cases diagnosed over the last 20 years has risen substantially due to increased awareness and improved geriatric care. Although MDS is increasingly diagnosed, the prevalence and prognosis of early-stage affected elderly are not completely known. OBJECTIVE: To evaluate the prevalence, characteristics and prognosis of newly diagnosed MDS patients hospitalized in an acute and subacute geriatric department. METHODS: Between 1993 and 1996, 3,275 patients hospitalized in the geriatric department of a teaching hospital for acute care or short-term rehabilitation were investigated for unexplained hematological abnormalities. Demographic, chronic comorbidities, cause of hospitalization, functional and cognitive status, hematological and other laboratory parameters were collected. RESULTS: Two hundred and forty-five (7.5%) patients had unexplained cytopenia, macrocytosis or monocytosis, of whom 37 (15%) were diagnosed as having MDS. Only 9 patients were hospitalized for evaluation of anemia, 28 for infections, cardiac, cerebrovascular events and other causes. Thirty-four patients had refractory anemia (RA), two had RA with ringed sideroblasts and 1 had RA with an excess of blasts (RAEB). The follow-up period was up to 70 months. No differences were found between demented and cognitively normal patients in age, sex, comorbidities or laboratory parameters. Comparison of survival curves (excluding the RAEB case) according to demographic, clinical and hematological parameters has shown that only dementia adversely affects survival, compared to cognitively normal patients (p = 0.024). CONCLUSIONS: MDS of the RA type is a common and incidental finding in older hospitalized patients. It is a frequent cause of anemia and other hematological abnormalities but has less significance on survival rates than dementia, although its full impact remains to be determined.