Purpose: We aimed to develop a reliable identification algorithm combining diagnostic codes with several treatment factors for inpatients with acute ischemic stroke (AIS) to conduct pharmacoepidemiological studies using the administrative database MID-NET ® in Japan.
Methods:We validated 11 identification algorithms based on 56 different diagnostic codes (International Classification of Diseases, Tenth Revision; ICD-10) using Diagnosis Procedure Combination (DPC) data combined with information on AIS therapeutic procedures added as "AND" condition or "OR" condition. The target population for this study was 366 randomly selected hospitalized patients with possible cases of AIS, defined as relevant ICD-10 codes and diagnostic imaging and prescription or surgical procedure, in three institutions between April 1, 2015 and March 31, 2017. We determined the positive predictive values (PPVs) of these identification algorithms based on comparisons with a gold standard consisting of chart reviews by experienced specialist physicians. Additionally, the sensitivities of them among 166 patients with the possible cases of AIS at a single institution were evaluated.Results: The PPVs were 0.618 (95% confidence interval [CI]: 0.566-0.667) to 0.909 (95% CI: 0.708-0.989) and progressively increased with adding or limiting information on AIS therapeutic procedures as "AND" condition in the identification algorithms. The PPVs for identification algorithms based on diagnostic codes I63.x were >0.8. However, the sensitivities progressively decreased to a maximum of $0.2 after adding information on AIS therapeutic procedures as "AND" condition.
Conclusions:The identification algorithms based on the combination of appropriate ICD-10 diagnostic codes in DPC data and other AIS treatment factors may be useful to studies for AIS at a national level using MID-NET ® .
von Hippel-Lindau (VHL) disease is characterized by neoplastic and cystic lesions, such as central nervous system (CNS) hemangioblastoma and clear cell renal cell carcinoma (RCC), arising in multiple organs. Here, we report a case of an RCC that metastasized to a spinal hemangioblastoma in a patient diagnosed with VHL disease. This is a unique case study because visceral neoplasms rarely metastasize to the CNS. The patient had undergone posterior fossa surgery for the removal of hemangioblastomas in the right cerebellar hemisphere as a child. He was diagnosed with RCC at the age of 20 years, and he underwent partial nephrectomy at the age of 35 years. The patient underwent surgical removal of a spinal tumor from Th8, which was also diagnosed as a hemangioblastoma at the age of 40. However, the residual spinal tumor rapidly regrew within 1.5 years. A second surgery was performed due to progressive leg motor weakness. The resected tumor from the second surgery had two distinct components between the tumor center and the margin. Immunohistochemistry of CD10, PAX 8, and inhibin A demonstrated the predominant region of the tumor was RCC. Pathological findings confirmed tumor-to-tumor metastasis of the RCC migrating into residual spinal hemangioblastoma. It can be challenging to distinguish hemangioblastoma from RCC in neuroimaging. We suggest that tumor-to-tumor metastasis should be considered as a differential diagnosis if benign tumors grow rapidly, even if the pathological diagnosis does not initially confirm malignancy. The biological mechanisms of RCC migrating into residual hemangioblastoma are discussed.
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