Nephrology Associates Medical Group Reports Data Breach Affecting Patient Information
Nephrology Associates Medical Group, a California-based healthcare provider serving Riverside and San Bernardino counties, disclosed a data security incident that may have compromised the protected health information (PHI) of certain patients. The breach was first detected on May 20, 2025, when suspicious activity was identified within the organization’s network. Immediate containment measures were implemented, and cybersecurity experts were engaged to investigate.
The investigation confirmed that an unauthorized actor had accessed the network and exfiltrated files containing sensitive data. On December 2, 2025, the medical group determined that some of the compromised files included patient PHI. The exposed information varies by individual but may include names, Social Security numbers, dates of birth, medical records, treatment details, health insurance information, billing data, and credentialing information.
In response, Nephrology Associates has set up a toll-free call center (844-443-1521) for affected patients, operating Monday through Friday from 6:30 a.m. to 3:30 p.m. PT. The incident underscores ongoing cybersecurity risks in the healthcare sector, particularly for organizations handling sensitive patient data.
Source: https://www.claimdepot.com/data-breach/nephrology-associates-2026
Nephrology Associates Medical Group cybersecurity rating report: https://www.rankiteo.com/company/nephrology-associates-medical-group
"id": "NEP1772497476",
"linkid": "nephrology-associates-medical-group",
"type": "Breach",
"date": "5/2025",
"severity": "85",
"impact": "4",
"explanation": "Attack with significant impact with customers data leaks"{'affected_entities': [{'customers_affected': 'Certain patients',
'industry': 'Healthcare',
'location': 'Riverside and San Bernardino counties, '
'California, USA',
'name': 'Nephrology Associates Medical Group',
'type': 'Healthcare Provider'}],
'customer_advisories': 'Toll-free call center established for affected '
'patients',
'data_breach': {'data_exfiltration': 'Yes',
'personally_identifiable_information': 'Names, Social '
'Security numbers, '
'dates of birth, '
'medical records, '
'treatment details, '
'health insurance '
'information, billing '
'data, credentialing '
'information',
'sensitivity_of_data': 'High',
'type_of_data_compromised': 'Protected health information '
'(PHI)'},
'date_detected': '2025-05-20',
'date_publicly_disclosed': '2025-12-02',
'description': 'Nephrology Associates Medical Group disclosed a data security '
'incident that may have compromised the protected health '
'information (PHI) of certain patients. The breach was '
'detected due to suspicious activity within the organization’s '
'network, and an unauthorized actor accessed and exfiltrated '
'files containing sensitive data.',
'impact': {'data_compromised': 'Protected health information (PHI), including '
'names, Social Security numbers, dates of '
'birth, medical records, treatment details, '
'health insurance information, billing data, '
'and credentialing information',
'identity_theft_risk': 'High'},
'investigation_status': 'Completed',
'references': [{'source': 'Nephrology Associates Medical Group Disclosure'}],
'response': {'communication_strategy': 'Toll-free call center (844-443-1521) '
'for affected patients, operating '
'Monday through Friday from 6:30 a.m. '
'to 3:30 p.m. PT',
'containment_measures': 'Immediate containment measures '
'implemented',
'incident_response_plan_activated': 'Yes',
'third_party_assistance': 'Cybersecurity experts'},
'threat_actor': 'Unauthorized actor',
'title': 'Nephrology Associates Medical Group Data Breach',
'type': 'Data Breach'}