Single Health Care Center Research Articles

Clinical Factors Associated With Mode of Death Following Cardiac Arrest

Background Death after resuscitation from cardiac arrest is common. Although associated factors have been identified, knowledge about their relationship with specific modes of death is limited. Objective To identify clinical factors associated with specific modes of death following cardiac arrest. Methods This study involved a retrospective medical record review of patients admitted to a single health care center from January 2015 to March 2020 after resuscitation from cardiac arrest who died during their index hospitalization. Mode of death was categorized as either brain death, withdrawal of life-sustaining therapies due to neurologic causes, death due to medical causes, or withdrawal of life-sustaining therapies due to patient preference. Clinical characteristics across modes of death were compared. Results The analysis included 731 patients. Death due to medical causes was the most common mode of death. Compared with the other groups of patients, those with brain death were younger, had fewer comorbidities, were more likely to have experienced unwitnessed and longer cardiac arrest, and had more severe acidosis and hyperglycemia on presentation. Patients who died owing to medical causes or withdrawal of life-sustaining therapies due to patient preference were older and had more comorbidities, fewer unfavorable cardiac arrest characteristics, and fewer days between cardiac arrest and death. Conclusions Significant associations were found between several clinical characteristics and specific mode of death following cardiac arrest. Decision-making regarding withdrawal of care after resuscitation from cardiac arrest should be based on a multimodal approach that takes account of a variety of personal and clinical factors.

Risk factors associated with restenosis in patients with percutaneous coronary intervention

ABSTRACT Objective: The objective of this study was to assess the risk factors associated with residual stenosis in patients with percutaneous transluminal coronary angioplasty (PTCA). Materials and Methods: A cross-sectional survey was conducted at a single health-care center among coronary artery disease patients who have undergone PTCA. Primary information including demographics and clinical characteristics, groups of pre- and postdilation balloons, and characteristics of culprits’ vessel flow were retrieved from medical records of each patient. Data were analyzed using descriptive and appropriate comparative statistics. Results: A total of 1000 patients were included in this study. The majority of patients were men (67.0%). Hypertension (HTN) and diabetes were the most common comorbid condition. Yukon Choice phosphorylcholine (PC)-elite (86.2%) was the most common stent used in patients with PTCA followed by Endeavor Sprint (12.7%). All of the patients (100%) underwent PTCA for single culprit vessel disease (SVD) while 30.2% of the patients underwent PTCA for two-vessel disease (2VD). The incidence of residual stenosis was 0.5% for SVD PTCA and 0.3% for 2VD PTCA. The 2VD group achieved thrombolysis in myocardial infarction flow Grade II postrevascularization in 98.6% of patients. Significant associations were observed between residual stenosis and various factors. HTN (odds ratio [OR]: 38.79, 95% confidence interval [CI]: 3.260-461.688; P = 0.004), diabetes mellitus (OR: 4.548, 95% CI: 0.036-63.948; P < 0.001), the use of a 0.014” × 190 cm guide (OR: 185.0, 95% CI: 25.922-1320.294; P < 0.001), and the presence of two-vessel disease (OR: 6.698, 95% CI: 1.221-36.749; P = 0.029) were found to be significantly associated with residual stenosis. Conclusion: Residual stenosis was observed in both SVD and 2VD PTCA however, presence of HTN and DM, and 2VD were identified as pronounced risk factors for residual stenosis.

Rotavirus and adenovirus in children evaluated for viral gastroenteritis at a single healthcare center in the Eastern Province of Saudi Arabia: A perspective of two decades.

The aim of this study was to determine the distribution of rotavirus and adenovirus in pediatric patients evaluated for viral gastroenteritis in a hospital in the Eastern Province of Saudi Arabia for 22 years. This was a retrospective study based in a secondary healthcare center in Saudi Arabia. Laboratory and demographic data were collected from hospital records for all pediatric patients (up to 14 years old) evaluated for viral gastroenteritis by rotavirus/adenovirus antigen detection kit from January 2000 to December 2022. Data were analyzed utilizing SPSS version 28.0. Categorical data were presented as frequency and percentages, whereas mean and standard deviations were computed for continuous variables. Chi-square test and t-test were used to determine statistical significance. The overall yields of antigen detection were 13.6% for rotavirus and 2.6% for adenovirus. Coinfection with both viruses was documented in 0.5% of the study population. Rotavirus was persistently detected in the past two decades with varying frequency, but the detection of adenovirus showed intervals of at least three consecutive years of zero confirmed cases. Before 2013, when the rotavirus vaccine was introduced in Saudi Arabia, rotavirus was much more prevalent than adenovirus (30% compared to 3.8% in 2010), but they became equally prevalent a decade after the introduction of the vaccine. Rotavirus gastroenteritis showed three different peaks in the year, in March, July, and December. Each peak was followed by a gradual decrease in prevalence before the next peak. Adenovirus, in contrast, was detected consistently around the year at rates between 2% and 5%. Rotavirus and adenovirus gastroenteritis have changed in prevalence in the past two decades. We found distinct seasonal patterns associated with rotavirus and adenovirus gastroenteritis. The utilization of virological testing for pediatric gastroenteritis with syndromic testing panels is to be encouraged to improve the knowledge of the true prevalence of enteric viruses.

Surgical treatment of pituitary neuroendocrine tumors with coexisting intracranial lesions: A case series and review of the literature.

Pituitary neuroendocrine tumors (PitNETs) are a diverse group of benign neoplasms that account for a significant proportion of intracranial tumors (13%). The coexistence of PitNET with other intracranial lesions, such as meningiomas and intracranial aneurysms, has been constantly reported in the literature; yet, the pathophysiological mechanisms remain unknown, and the appropriate management is controversial. This study aims to describe the clinical characteristics, surgical treatment, and outcomes of patients with PitNET with coexisting intracranial lesions in a single healthcare center. A retrospective analysis was conducted on 12 patients who underwent surgical treatment for PitNET and another intracranial lesion at our single tertiary referral center over 15 years from January 2008 to May 2023. Among these coexisting lesions, aneurysms were the most commonly found (41.67%), followed by meningiomas (33.33%). Surgical intervention for both lesions was performed in a single-stage procedure for most cases (75%), employing transcranial, endoscopic endonasal, and combined approaches. We found low preoperative Karnofsky Performance Scale scores in three patients, with significant differences in functional outcomes. These findings contribute to the limited knowledge about PitNET coexisting with other intracranial lesions and emphasize the importance of patient-tailored, multidisciplinary management in these unusual scenarios.

Diagnostic yield and accuracy of nipple discharge cytology as a screening tool for detection of breast cancer

Background: Nipple discharge (ND) is one of the most common symptoms encountered by patients with breast disease and can be caused by benign or malignant conditions. ND cytology is a simple non-invasive method to help determine the pathology behind the discharge. This study looks into the diagnostic value and accuracy of ND cytology. Methods: A retrospective study was performed at a single healthcare center, by evaluating the ND cytology samples and comparing their results with corresponding histopathologic samples from January 2014 to December 2019. Additional data for comparison included ND color, appearance, and discharge laterality. Results: A total of 499 samples of ND cytology were found, and 98 of these samples had a corresponding histopathologic sample. The overall diagnostic yield was found to be 7.4%, with 462 negative ND cytology samples. The diagnostic yield is highest with bloody discharge (29.8%) and in patients presenting with a unilateral ND (10.8%). Through comparison with corresponding histopathologic samples, the sensitivity of ND cytology in the study is 44.4%, specificity 86.5%, positive predictive value 25%, and negative predictive value 83.9%. Conclusion: ND cytology is a simple and useful tool for assessing the underlying pathology. Due to the low number of histological samples relating to the cytological samples, larger data would benefit further research. As there are many controversies about ND cytology value, it should be in complement with other investigations to have a better judgment.

Flexible and secure access control for EHR sharing based on blockchain

With the rapid development of the healthcare industry, many Electronic Health Records (EHRs) have emerged in different healthcare centers. However, lots of personal medical data are stored directly in plaintext at a single healthcare center, which makes it suffer from the single point of failure and brings many security and privacy issues such as privacy information leakage or tampering. The combination of blockchain and attributed-based cryptography can effectively solve the above problems. Therefore, in order to enable flexible fine-grained access control and efficient data retrieval while achieving privacy protection, we employ the ciphertext-policy attributed-based encryption (CP-ABE) and ciphertext-policy attribute-based searchable encryption (CP-ABSE) to propose a hidden policy attribute-based access control scheme. In addition, we combine consortium blockchain and smart contract to provide secure and reliable search and outsourcing decryption. Finally, through the security analysis and experimental results, we demonstrate that our scheme is secure and efficient.

Awareness and Attitude Toward Epidural Analgesia During Labor Among Pregnant Women in Taif City: A Hospital-Based Study.

Objectives This study aimed to investigate the awareness and attitudes towards epidural analgesia (EA) among pregnant women in Taif City, Saudi Arabia. The rationale was to identify potential barriers to the acceptance and use of EA, which is an effective pain management option during labor. Methods We conducted a cross-sectional survey at a single healthcare center in Taif City. The participants, pregnant women visiting the center, were recruited using a convenience sampling method. Data collection was facilitated by a questionnaire distributed through a quick response (QR) code. The questionnaire assessed demographic information, awareness levels, previous exposure to EA, and personal attitudes toward its use during labor. Data analysis focused on quantifying the levels of awareness and identifying patterns in attitudes. Results The results revealed a low level of awareness about EA among the participants, with a significant proportion having never been exposed to it before the survey. Attitudes towards EA were varied, with some expressing openness to its use and others displaying apprehension or resistance, which appeared to be influenced by cultural perceptions and a lack of information. Conclusions The study highlighted a substantial lack of awareness and varied attitudes towards EA among pregnant women in Taif City. Educational interventions are necessary to increase awareness and address cultural misconceptions. The study's limited scope and potential sample bias suggest the need for broader culturally tailored research to inform strategies for improving the acceptance and utilization of labor analgesia.

Microvascular surgery training in a low volume setting: a single healthcare center experience

Microvascular surgery training in a low volume setting: a single healthcare center experience

Association of mycophenolate and azathioprine use with cognitive function in systemic lupus.

Cognitive dysfunction (CD) is a common manifestation of SLE that can have detrimental consequences for those affected. To date, no treatments have been approved for SLE-CD. This study aims to assess the association of azathioprine (AZA) and mycophenolate (MMF) use with SLE-CD, given thatthese medications have demonstrated neuroprotective qualities in prior studies. Consecutive adult SLE patients presenting to a single healthcare center were considered for participation. The ACR neuropsychological battery for SLE was administered to consenting patients at 0, 6 and 12 months. Scores were compared with age- and sex-matched controls. Primary outcome was CD, defined as a z-score ≤-1.5 in two or more cognitive domains. Mixed-effects logistic regression models were constructed to estimate the odds of CD with respect to AZA and MMF use. A total of 300 participants representing 676 patient visits completed the study; 114 (38%) met criteria for CD at baseline. The cumulative AZA dose (g/kg) was associated with reduced odds of CD [odds ratio (OR) 0.76 (95% CI 0.58, 0.98), P = 0.04]. Years of AZA treatment was also associated with reduced odds of CD [OR 0.72 (95% CI 0.54, 0.97), P = 0.03]. MMF use was not associated with CD. AZA use was associated with significantly lower odds of SLE-CD, while MMF use was not. Additional studies are warranted to further investigate the relationship of AZA and SLE-CD.

Natural Language Processing for Information Extraction of Gastric Diseases and Its Application in Large-Scale Clinical Research.

Background and Aims: The utility of clinical information from esophagogastroduodenoscopy (EGD) reports has been limited because of its unstructured narrative format. We developed a natural language processing (NLP) pipeline that automatically extracts information about gastric diseases from unstructured EGD reports and demonstrated its applicability in clinical research. Methods: An NLP pipeline was developed using 2000 EGD and associated pathology reports that were retrieved from a single healthcare center. The pipeline extracted clinical information, including the presence, location, and size, for 10 gastric diseases from the EGD reports. It was validated with 1000 EGD reports by evaluating sensitivity, positive predictive value (PPV), accuracy, and F1 score. The pipeline was applied to 248,966 EGD reports from 2010–2019 to identify patient demographics and clinical information for 10 gastric diseases. Results: For gastritis information extraction, we achieved an overall sensitivity, PPV, accuracy, and F1 score of 0.966, 0.972, 0.996, and 0.967, respectively. Other gastric diseases, such as ulcers, and neoplastic diseases achieved an overall sensitivity, PPV, accuracy, and F1 score of 0.975, 0.982, 0.999, and 0.978, respectively. The study of EGD data of over 10 years revealed the demographics of patients with gastric diseases by sex and age. In addition, the study identified the extent and locations of gastritis and other gastric diseases, respectively. Conclusions: We demonstrated the feasibility of the NLP pipeline providing an automated extraction of gastric disease information from EGD reports. Incorporating the pipeline can facilitate large-scale clinical research to better understand gastric diseases.

The Usefulness of Assessing Heart Rate Variability in Patients with Acute Myocardial Infarction (HeaRt-V-AMI).

Background: Heart rate variability (HRV) could have independent and critical prognostic values in patients admitted for ST segment elevation myocardial infarction (STEMI). There are limited data in the literature regarding HRV assessment in STEMI setting. Thus, we aim to investigate the potential correlations between HRV and adverse outcomes in a contemporary cohort of patients presenting with STEMI undergoing primary percutaneous coronary intervention (PCI). Methods: We will perform a prospective, observational cohort study in a single healthcare center. Adult patients aged ≥18 years presenting with STEMI in sinus rhythm will be enrolled for primary PCI within 12 h from symptoms onset. Time domain, frequency domain, and nonlinear HRV parameters will be measured using a medically approved wrist-wearable device for 5 min segments during myocardial revascularization by primary PCI. Additional HRV measurements will be performed one and six months from the index event. The primary composite outcome will include all-cause mortality and major adverse cardiovascular events (during the hospital stay, one month, and one year following admission). Several secondary outcomes will be analyzed: individual components of the primary composite outcome, target lesion revascularization, hospitalizations for heart failure, ventricular arrhythmias, left ventricular ejection fraction, and left ventricular diastolic function. Conclusions: Our study will enlighten the reliability and usefulness of HRV evaluation as a prognostic marker in contemporary patients with STEMI. The potential validation of HRV as a risk marker for adverse outcomes following STEMI will ensure a background for including HRV parameters in future risk scores and guidelines.

Bioethics in an oncological surgery unit during the COVID-19 pandemic: the Verona experience

The spread of COVID-19 has overwhelmed medical facilities across the globe, with patients filling beds in both regular wards and in intensive care units. The repurposing of hospital facilities has resulted in a dramatic decrease in the capacity of hospitals—in terms of available beds, surgical facilities, and medical and nursing staff— to care for oncology patients. The Italian National Board of Bioethics provided precise and homogeneous guidelines for the allocation of the scarce resources available. In our experience, strictly following these general guidelines and not considering the clinical vocation of each single health care center did not allow us to resume usual activities but generated further confusion in resource allocation. To face the scarcity of available resources and guarantee our patients fair access to the health care system we created a surgical triage with four fundamental steps. We took into consideration “ well defined and widely accepted clinical prognostic factors ” as stated by the Italian Society of Anesthesia and Resuscitation. We were able to draw up a list of patients giving priority to those who theoretically should have a greater chance of overcoming their critical situation. The age criterion has also been used in the overall evaluation of different cure options in each case, but it has never been considered on its own or outside the other clinical parameters. Although not considered acceptable by many we had to forcefully adopt the criterion of comparison between patients to give priority to those most in need of immediate care.

Indications, Results and Complications of Prenatal Genetic Diagnostic Testing at a Single Healthcare Center

Indications, Results and Complications of Prenatal Genetic Diagnostic Testing at a Single Healthcare Center

Clinico-pathological profile of pancytopenia patients in a single health care centre of northern India.

ABSTRACTBackground:Pancytopenia is a clinical outcome of various pathological conditions ranging from bone marrow suppression, bone marrow infiltration, infections, hypersplenism, haemolysis, and haematological malignancies. As such is the most common cause in drug induced (chemotherapy) bone marrow suppression. As most of these patients first contact their primary care physicians, a quick workup will resolve many diagnosis and can give a hint towards a life threatening condition too.Material and Methods:We included all patients admitted with pancytopenia at our tertiary care centre except those who were drug induced. They were evaluated and given appropriate treatment.Results:We observed 73 patients in a year, after excluding drug-induced pancytopenia, and showed aplastic anaemia was the foremost cause (31.5%) followed by vitamin B12 deficiency (19.2%), infections (13.7%), hypersplenism and haematological malignancies.Conclusion:Majority of adult patients admitted with pancytopenia are diagnosed to have curable cause like vitamin deficiency and infections but significant number was also of aplastic anaemia, a condition that requires specialist care.

Any Postoperative Surveillance Improves Survival after Endovascular Repair of Ruptured Abdominal Aortic Aneurysms

Endovascular aortic repair (EVAR) has advanced the care of patients with ruptured abdominal aortic aneurysms (rAAA) with improved early postoperative morbidity and mortality. However, this comes at the cost of a rigorous postoperative surveillance schedule to monitor for further aneurysmal degeneration. Adherence to surveillance recommendations is known to be poor in the elective setting, but has yet to be studied in the ruptured population. The aim of this study is to investigate predictors of incomplete surveillance after EVAR for rAAA (rEVAR) and examine how adherence impacts outcomes. This was a retrospective case control study of patients undergoing rEVAR at a multiple hospital single healthcare center (2003-2020). Patients were excluded if they underwent open conversion during their index hospitalization or died within 60 days of surgery. Follow-up was broadly categorized as complete surveillance (60-day postoperative visit and annually thereafter) or incomplete surveillance, comprising both patients with less than recommended surveillance (minimal surveillance) and completely lost to follow-up (LTF). Any follow-up was defined as patients with complete or minimal surveillance. We investigated predictors of complete versus incomplete surveillance by multivariate logistic regression. Secondary outcomes included overall survival and cumulative incidence of reintervention controlling for the competing risk of mortality, generating hazard ratios (HR) and subdistribution hazard ratios (SHR). One-hundred and sixty patients (mean age 74 ± 10.1 years, 81.2% male) out of 673 total rAAA met study inclusion criteria. Complete surveillance was seen in 41.3% of our cohort, with the remainder with minimal surveillance (29.4%) or LTF (29.4%). Incomplete surveillance was associated with male sex (odds ratio [OR] 2.56; 95% CI 1.02-6.43), lack of a primary care provider (PCP; OR 0.20; 95% CI 0.04-0.99), and longer driving distance from home to treating hospital (OR 2.37; 95% CI 1.08-5.20). Survival was not different between complete and incomplete surveillance groups, however any follow-up conferred improved survival over LTF (HR 0.57; 95% CI 0.331-0.997; P=0.049). Reintervention was associated with incomplete surveillance (SHR 0.29; 95% CI 0.11-0.75), and discharge to a facility (SHR 0.25; 95% CI 0.067-0.94). Incomplete surveillance was observed in over 50% of patients who underwent rEVAR and was associated with male sex, lack of PCP, and longer driving distance. Any follow-up conferred a survival benefit, yet incomplete surveillance was associated with a lower risk of reintervention. Targeted strategies to prevent LTF, and less stringent, personalized follow-up plans that may confer similar survival benefit with better patient adherence should be investigated.

Any Postoperative Surveillance Improves Survival After Endovascular Repair of Ruptured Abdominal Aortic Aneurysms

Endovascular aortic repair (EVAR) has become first-line therapy for ruptured abdominal aortic aneurysms (rAAA). Rigorous surveillance imaging after EVAR is recommended due to the high risk of endograft complications in this population. Follow-up compliance is known to be poor after elective EVAR but has not been studied in patients after EVAR for rAAA (rEVAR). Our objective is to investigate patient factors that predict incomplete surveillance and examine how compliance impacts outcomes after rEVAR. This was a retrospective observational study of patients undergoing rEVAR at a multiple hospital single health care center (2003-2020). Patients were excluded if they underwent open conversion during their index hospitalization or died within 60 days of surgery. Follow-up surveillance was broadly categorized as complete surveillance (1-month postoperative visit and annually thereafter) or incomplete surveillance, which comprised both patients completely lost to follow-up (LTF) and those with less than recommended postoperative surveillance (minimal compliance; MC). We investigated predictors of complete vs incomplete surveillance by multivariate logistic regression. Kaplan-Meier curves were generated for surveillance groups and compared using the log-rank test. Multivariate Cox regression was used to explore the effect of surveillance compliance on survival. One-hundred sixty patients (mean age: 74 ± 10.1 years, 81.2% male) out of 673 total rAAA met study inclusion criteria. The majority were white (96.5%) with a history of tobacco use (69.7%), hypertension (59.6%), and coronary artery disease (56.0%). Complete surveillance was seen in 41.3% of our cohort. The remainder had either MC (29.4%) or were LTF (29.4%). On multivariable regression, longer driving distance from home to treating hospital, male sex, and lack of a primary care provider (PCP) were associated with incomplete surveillance. Death occurred in 65 (40.6%) and reintervention in 25 (15.6%) patients during the study period. Survival was not different between complete and incomplete surveillance groups (P = .24). Subgroup analysis revealed a similar survival for patients with complete surveillance and those with minimal compliance. On multivariate Cox analysis, any follow-up conferred improved survival over LTF (hazard ratio, 0.57; 95% confidence interval, 0.331-0.997; P = .049) (Fig). Incomplete follow-up surveillance was observed in over 50% of patients who underwent rEVAR and was associated with longer driving distance, male sex, and lack of listed PCP. Any follow-up after rEVAR conferred a survival advantage. Thus, identification of patient level risk factors for poor follow-up before discharge will guide the design of mitigation strategies to prevent LTF.

Rituximab in refractory myasthenia gravis: experience in a single healthcare center in Mexico. (2977)

Rituximab in refractory myasthenia gravis: experience in a single healthcare center in Mexico. (2977)

Rituximab in Refractory Myasthenia Gravis: Experience in a Single Healthcare Center in Mexico.

Background: Ten to fifteen percent of patients with myasthenia gravis (MG) have treatment-refractory disease. In short series and case reports, rituximab has proven to be effective in refractory MG.Methods: A retrospective, longitudinal study was conducted. Recruitment was performed in an MG cohort from a single third-level healthcare center in Mexico. The selection included refractory MG patients that were treated with rituximab. Response after rituximab therapy was assessed with MG composite score (MGCS) and prednisone dose reduction at 6, 12, and 18 months after initiation. Wilcoxon signed-rank test was used to evaluate differences between related groups for non-continual variables. P<0.05 was considered statistically significant.Results: Ten patients (7%) fulfilled criteria for refractory MG, and eight of them were treated with rituximab. The mean age at MG diagnosis was 25.5 (±2) years, with a female predominance (75%). All our patients (100%) had positive acetylcholine receptor (AchR) antibodies. The median MG duration was six years (interquartile range [IQR] 4.2-6) before rituximab initiation. All patients were previously treated with azathioprine and 50% additionally with cyclophosphamide. The median prednisone doses before rituximab treatment and 18-month follow-up were 50 mg (IQR 30-50 mg) and 10 mg (IQR 0-20 mg), respectively (p=0.011). The median baseline MGCS and at 18-month follow-up were 19.5 (IQR 11-31) and 6 (IQR0-16), respectively (p = 0.012).Conclusion: Rituximab appears to be associated with clinical improvement and prednisone dose reduction in Latin-American patients diagnosed with anti-AchR MG. Our findings need to be interpreted in light of the limitations mentioned.

Effect of the COVID-19 pandemic on CT scans ordered from the emergency department for abdominal complaints.

PurposeThe COVID-19 pandemic has affected healthcare systems and patients alike across the USA. We seek to elucidate changes in abdominal imaging ordered from the emergency department (ED) in a healthcare system undergoing non-surge conditions in April 2020 compared to April 2019.MethodsWe performed a retrospective, observational study comparing patients undergoing CT scans of the abdomen and pelvis ordered from the ED in April 2020 vs. April 2019 at a single healthcare center. Via review of the radiology report and electronic medical record, we determined the positive or negative status of these scans. We evaluated percentages of positive CT scans and differences in outcomes, including admission rates, interventions, and mortality.ResultsComparing 2020 to 2019, there was a 31.6% decrease in the number of CT scans performed from the ED. We found a higher percentage of positive CT findings, 58.2% vs. 50.8% (p = 0.025), and increased admission rates, 40.8% vs. 34.1% (p = 0.036). Differences were found in rates of appendicitis, colitis, and cholangitis. No difference was found in ICU admissions, interventions, or in-hospital mortality.ConclusionDuring the COVID-19 pandemic in a region undergoing non-surge conditions, we found increased rates of positive CT scans performed from the ED for abdominal complaints with an increased percentage of hospital admissions compared to a control year. No differences in ICU admissions or rates of procedural intervention were found to suggest higher acuity of pathology on presentation. Our findings suggest appropriately decreased healthcare utilization in our study period, driven by pre-hospital patient self-selection.

MedShare: A Privacy-Preserving Medical Data Sharing System by Using Blockchain

Electronic Health Record (EHR) and its privacy have attracted widespread attention with the development of the healthcare industry in recent years. As locking medical data in a single healthcare center causes information isolation, healthcare centers are motivated to build medical data sharing systems. However, existing systems highly rely on the trusted centralized servers, which are vulnerable to distributed denial of service (DDoS) attacks and the single point of failure. Moreover, it is a non-trivial matter to authorize multiple users to search and access EHR in a privacy-preserving manner. In this paper, we propose MedShare, a decentralized framework for secure EHR sharing. Our design utilizes the smart contract technique of blockchain to establish a trusted platform for healthcare centers to share their encrypted EHR. Considering that fine-grained access control is essential in practical EHR sharing service, we devise a constant-size attribute-based encryption (ABE) scheme, where the access policy is embedded in search result on the blockchain. Besides, we propose an efficient scheme that enables authorized MedShare users to perform multi-keyword boolean search operations over encrypted EHR. We formally analyze the security strengths and implement the system prototype on Ethereum. Evaluation results demonstrate that MedShare is efficient for EHR sharing.