Government agencies might be the perfect setting to check the effect of electronic records on health care networks and storage systems. All the factors are present for an extreme information technology stress test: large concentrations of paper and electronic records, huge patient populations - the Defense Department alone has 9.2 million health beneficiaries - and in the aftermath of health emergencies such as Hurricane Katrina, patrons who are running out of patience with inefficiency.
Although predicting storage demands can be tricky, some good models exist. The military has deployed about 60 percent of its $1.2 billion electronic health record (EHR) system, called the Armed Forces Health Longitudinal Technology Application. It contains 8 million patient records and uses about 9 terabytes of disk storage, or about half of its Hewlett-Packard storage system. Each record can consume 10M to 100M of data storage.
Faced with managing thousands of patient records, those megabytes can quickly increase to terabytes of storage, and not just any storage. High-performance EHR systems require first-tier online storage.
"You have to be able to read the medical record as fast as flipping a sheet of paper," said Col. Victor Eilenfield, program manager of the development, implementation and maintenance of clinical information technologies at the Military Health System.
On such a scale, access is as important as speed. "Doctors need the data to be always available," said Dennis Proul, chief information officer at Stony Brook University Hospital and Health Sciences Center in Stony Brook, N.Y.
The requirements point to high-performance magnetic disk storage, either replicated or mirrored. Despite advances in optical and tiered storage strategies, anything other than primary magnetic online disk will not suffice, experts say.
Assessing the impact
"EHR will absolutely impact the IT infrastructure, but how much [of] an impact depends on the organization," said Nick Beard, director of health care technologies at PricewaterhouseCoopers. For a large hospital with a sophisticated IT infrastructure, the impact should be incremental.
The biggest factor affecting EHR storage is the content of the clinical data repository (CDR), which forms the core of any EHR system.
"The impact of EHR on the IT infrastructure depends on the degree of completeness of the CDR," Beard said. If the CDR collects data from only a handful of feeder systems - such as nursing, pharmacy and clinical documentation - the impact will be small. When the CDR expands to encompass radiology, laboratory and digital imaging systems, storage requirements will increase.
The IT architecture also influences storage requirements. "The question is whether you have a single integrated record or not," Beard said. The storage requirements of such records are greater than those for federated records, in which subsystems can instantly pull data to respond to queries. Tapping data stored elsewhere allows for a smaller core patient record. A federated approach, however, imposes greater network requirements and has other drawbacks. "In general, the federated approach is less effective," he said.
However you do it, adopting an EHR system is a major undertaking. Stony Brook is halfway through a five-year, $30 million EHR conversion. One of the first steps was a major IT infrastructure upgrade that included new fault-tolerant servers, faster and more reliable networks, and mirrored storage.
Stony Brook stores its EHRs on an IBM enterprise storage server, and it mirrors stored data at a backup site. Departmental systems separately store information from picture archiving and communications systems, cardiology and anesthesia. "We don't store everything in the EHR," Proul said. "Like a paper chart, the EHR doesn't have all the data."
On a smaller scale, the George Washington University Medical Faculty Associates moved its group practice of more than 200 doctors to an EHR system, which required consolidating data from dozens of different kinds of paper charts. Initially, the group used storage attached to its existing servers.
"As we expanded usage and wanted faster response, we invested in new hardware and [Redundant Arrays of Independent Disks] and [designed] the system for growth," said Dr. Ryan Bosch, who led the project.
The group's EHR system now uses a high-performance storage array, which is backed up on tape during the day. In the evening, the organization moves a copy offsite. "We have three degrees of redundancy," Bosch said. The cost of the new infrastructure, however, did not prove to be an obstacle. "Whatever the cost of the storage, it is insignificant compared to the cost of paper records," he said. By changing to an EHR system, the practice eliminated the expense of maintaining entire rooms of paper records and improved efficiency and the quality of patient care.
Although DOD, Stony Brook and the George Washington University group deployed machine-readable EHRs, some organizations have opted for image storage as an interim solution.
The Social Security Administration's Office of Disability Systems, for example, processes 12.5 million pages of health records a month and stores them electronically. But "the vast majority come in as paper," said Jerry Berson, the office's associate commissioner.
An outside contractor scans the paper records and returns them to Berson's staff for storage as an electronic image, not a machine-readable file. Of the 12.5 million pages received in November 2005, a typical month, only 1.8 million arrived electronically, and most of those were fax images.
The office stores the health records in a 5.5 terabyte IBM DB2 database. The storage consists of a Hitachi Data Systems disk array configured with RAID and a high-performance cache. The storage attaches directly to the DB2 host, from which users can access the files via the network as part of the claim evaluation process.
"We don't really get true electronic files although that's where the big benefits are," Berson said. "We'd like to get started with electronic records, but we're not there yet."
Maintaining high-performance health storage at low cost is an even greater hurdle. Through the WorldVistA program, the Department of Veterans Affairs aims to make its VistA EHR system available at low cost to any health organization, regardless of location. Health care providers can download the public domain system, which runs on low-cost, Intel-based servers.
"We have packaged WorldVistA to be affordable," said Joseph Dal Molin, a director of the VA's program.
The system uses the MUMPS programming language and integrated database, which reduces the IT resources needed. "You could run it on an old notebook computer with a Pentium processor, little memory and a small disk," Dal Molin said. "For even a large implementation, the server and storage requirements would be a drop in the bucket."
For IT managers, the move to EHRs should not cause major headaches. Although such systems require large amounts of primary high-performance, high-availability online disk storage, vendors have been providing that for years.
"Yes, it's a major commitment to storage." Proul said. "But storage costs keep coming down so the investment is not a big