While patients and doctors often worry about medical records being hacked by cybercriminals and Internet snoops, the most common cause of health data breaches is physical theft of computing gear, according to reports by the U.S. Dept of Health and Human Services.

Under the HITECH Act, HHS is required to post a list of incidents involving breaches and unsecured protected health information affecting 500 or more people. The HHS listing of the incidents reveals the top causes of breaches to be theft, not hacking of data.

Of the 288 HIPAA breaches listed on the HHS site, physical theft is at the root of more than 49% of the violations, according to analysis by software research and consulting firm, Software Advisor.

Meanwhile, human error and careless or accidental physical losses--such as losing a laptop with patient data--accounted for 14% of the incidents; unauthorized access and disclosure was involved in 16% of the cases; and improper disposal was the root of 5% of the incidents.

Despite common fears by patients and healthcare providers about of intrusions by black hats, hacking was involved in just 6% of the incidents.

Approximately 9% of the incidents involved a combination of breaches.

According the HHS, the largest data breach of all involved the theft of portal disk drive stolen from Health Net Inc. in California. The January 2011 incident affected 1.9 million individuals.

As for data breaches that involved lost computing gear, the largest incident occurred at South Shore Hospital in South Weymouth, Mass, affecting 800,000 individuals.

The January 2010 incident involved outdated patient data that was stored in e-medical records and on portable electronic devices that had been shipped by the hospital to Archive Data Solutions (formerly called Iron Mountain Data Products) for disposal.

However, a number of the boxes containing the records reportedly never arrived at the third-party data management company. The South Shore Hospital event was the fifth largest data breach incident reported in the HHS list.

Meanwhile, the largest breach involving hacking occurred last November and involved health data at Seacoast Radiology PA in New Hampshire. The incident affected 231,400 individuals.

Among some of the other larger health data breaches was a hacking incident in February 2010 involving records of the University of Texas in Arlington. The breach of prescription records--which included names of patients, diagnostic codes, medications names and some social security numbers--involved a network file server and affected approximately 27,000 individuals, according the HHS report.

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