A refactor of https://gist.github.com/Nasah-Kuma/35e6609ba8e37699132f1c963907ed35 using enums

healthRecordRepoRef.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract HealthRecordRepository {
    enum AdmissionStatus { Admitted, NotAdmitted }

    struct HealthRecord {
        uint256 recordID;
        string patientName;
        uint256 age;
        string diagnosis;
        string treatment;
        string[] medications;
        AdmissionStatus admissionStatus;
    }

    mapping(address => HealthRecord[]) private patientRecords;

    function addHealthRecord(
        string memory _patientName,
        uint256 _age,
        string memory _diagnosis,
        string memory _treatment,
        string[] memory _medications,
        AdmissionStatus _admissionStatus
    ) public {
        HealthRecord memory newRecord = HealthRecord({
            recordID: patientRecords[msg.sender].length,
            patientName: _patientName,
            age: _age,
            diagnosis: _diagnosis,
            treatment: _treatment,
            medications: _medications,
            admissionStatus: _admissionStatus
        });
        
        patientRecords[msg.sender].push(newRecord);
    }

    function getPatientRecords(address _patientAddress)
        public
        view
        returns (HealthRecord[] memory)
    {
        return patientRecords[_patientAddress];
    }

    function getRecordByID(address _patientAddress, uint256 _recordID)
        public
        view
        returns (HealthRecord memory)
    {
        require(
            _recordID < patientRecords[_patientAddress].length,
            "Invalid record ID"
        );
        return patientRecords[_patientAddress][_recordID];
    }
}