# Blockchain Technology in Healthcare: A Comprehensive Review and Directions for Future Research
## 6 Conclusions  
The blockchain technology is gaining significant attention from individuals, as well as organizations of nearly all kinds and dimensions. It is capable of transforming the traditional industry with its features, which include decentralization, anonymity, persistency, and auditability [32; 169; 170]. The blockchain technology is expected to reshape the healthcare ecosystem. Not only the process will be transparent and secure, but also the quality of healthcare will be increased at a lower cost. In this paper, we discussed various blockchain applications in the healthcare industry and identified the major research initiatives as well as future research opportunities. Specifically, we presented current research on health data management and how blockchain will empower patients and stream line the sharing process of health data. We found that there is a consensus among researchers that, with blockchain technology, patient data will be truly owned and controlled by the rightful owner of the data, i.e., the patient. The blockchain allows for health records to be time-stamped so that no one can tamper with them after becoming part of the distributor ledger. The patients will have the right to decide who can and cannot access their data and for what purpose. However, there are still several open challenges that require further investigation. For example, cross-border sharing of health data where different and often conflicting jurisdictions exist may hinder the benefit of blockchain's data sharing. Indeed, the expectation of individual's privacy varies from one country to another based on the government regulations. Therefore, future research on regulation, standardization, and cross-border health data retrieving policies including retention and usage intention are duly urgent. Another potential problem that is under-researched is the capability of the blockchain to store and process massive data access transactions in a timely manner. As the volume of transactions increases, the delay of mining blocks in private or public blockchain's will increase exponentially. Therefore, there is a need for innovative mechanisms and algorithms to minimize the mining delays. Furthermore, we discussed current research of blockchain on healthcare SCM. In particular, the applicability of blockchain to address trust degradation and to strengthen data transparency on the clinical trials. Several researchers propose the use of blockchain to improve the scientific credibility of findings from clinical trials, which could be undermined by problems such as missing data and selective publication. We also discussed the issue of tracking drugs; it is clear that blockchain technology will be an indispensable tool for pharmacist and healthcare providers to properly and timely authenticate the flow of legitimate drugs and their delivery to the patients. However, further research on robust tracking mechanisms that monitor the registration of the products is needed. Current tracking systems that rely on RFIDs and Barcodes are not immune from tampering since these codes are sent as fixed values in the supply chain process which can be modified/copied by counterfeiters. Other cases such as billing and payment management were presented in this paper as future research issues. Claims and billing in the healthcare sector are being continuously abused, but can be resolved or diminished by using a transparent system such asblockchain. Finally, we presented the application of blockchain in IoMT. Healthcare systems of the 21 st century will consist of various devices connecting patients (e.g., remote healthcare services, wearable devices, etc.) with their caregivers. These systems generate data continuously and can be subject to malicious attacks while in transmission at various levels of the underlying communication network. In this paper, we discussed several research studies that propose tamper-resistant systems using blockchain technology to ensure the fidelity of health data.