Underutilization of peritoneal dialysis: the role of the nephrologist's referral pattern.

BACKGROUND: The incidence of end-stage renal disease is increasing, placing a tremendous burden on health care resources. Peritoneal dialysis (PD) is cheaper than hemodialysis and has many potential advantages and few contraindications as an initial modality selection. This study examined differences in patient PD attempt rates between nephrologists using technique survival and mortality as outcomes. METHODS: We performed a retrospective review of the Manitoba Renal Program databases from January 2004 to January 2010. Analysis of 630 patients who commenced dialysis and had demographic data available was performed. A genetic matching algorithm was used to balance potential differences between patient characteristics. Each nephrologist was then compared against their peers to calculate a PD attempt rate. The highest attempt rate group was compared with the lowest. RESULTS: When comparing PD attempt rates between groups, all the results were significant. PD technique survival at >90 days showed no significant differences (P = 0.42). Patient mortality at >90 days was also not significant when comparing groups (P = 0.14). CONCLUSIONS: Our data suggest that when comparing the low- with high-attempt groups, the factors limiting PD utilization do not include on-site availability of PD, case mix, funding, patient location or reimbursement. Aggressive approaches of starting more patients on PD did not lead to lower technique survival or higher mortality rates. If the PD attempt rate was maximized, a significant amount of money and resources could be saved or directed toward helping a larger population without significant harm to patients.

Video-on-demand network design and maintenance using fuzzy optimization.

Video-on-demand (VoD) is the entertainment source that, in the future, will likely overtake regular television in many aspects. Although many companies have deployed working VoD services, some aspects of the VoD should still undergo further improvement in order for it to reach to the foreseen potentials. An important aspect of a VoD system is the underlying network in which it operates. According to the huge number of customers in this network, it should be carefully designed to fulfill certain performance criteria. This process should be capable of finding optimal locations for the nodes of the network as well as determining the content that should be cached in each one. While this problem is categorized in the general group of network optimization problems, its specific characteristics demand a new solution to be sought for it. In this paper, which is inspired by the successful use of fuzzy optimization in similar problems in other fields, a fuzzy objective function that is heuristically shown to minimize the communication cost in a VoD network is derived while also controlling the storage cost. Then, an iterative algorithm is proposed to find a locally optimal solution to the proposed objective function. Capitalizing on the unrepeatable tendency of the proposed algorithm, a heuristic method for picking a good solution from a bundle of solutions produced by the proposed algorithm is also suggested. This paper includes a formal statement of the problem and its mathematical analysis. In addition, different scenarios in which the proposed algorithm can be utilized are discussed.