Comorbidities and costs vary with back pain severity

[Guest guest]

November 2006 Biomechanics Magazine

http://www.biomech.com/showArticle.jhtml?articleID=193700271

Comorbidities and costs vary with back pain severity

By: Lori Rochelle Roniger

Low back pain sufferers with a higher number of back pain episodes

had a significantly greater likelihood of experiencing

comorbidities, according to the results of a study published in

September in BMC (BioMed Central) Musculoskeletal Disorders.

The research, which was conducted using Kaiser Permanente Colorado

data, also found that a small proportion of patients with recurrent

LBP had relatively high medical costs.

" We were surprised by the number of significant comorbidities that

are prevalent in patients who exhibit multiple back pain events, "

said Debra Ritzwoller, health economist and research scientist at

Kaiser Colorado and the study's lead author.

The researchers examined patient data for 1996 through 2001 and

included 16,567 patients in their analysis. The patients were

required to have been diagnosed with LBP in 1997 or 1998 for the

first time since they enrolled with Kaiser, and to have then been at

least 18 years old. Additionally, they had to have been Kaiser

members for the year preceding the diagnosis and to have remained

enrolled for the next two years. Diagnosis was based on

International Classification of Diseases, Ninth Revision (ICD-9),

codes consistent with mechanical LBP and excluded back pain

secondary to other conditions like osteomyelitis, pregnancy,

fracture, dislocation, or vehicular accident.

The investigators calculated the number of 30-day periods during the

two years following the initial diagnosis during which each patient

had at least one episode of LBP that led to visiting a Kaiser

healthcare provider. They found that 67% had one such event, 17% had

two, 11% had between three and five, and 5% had between six and 22.

The initial diagnosis varied significantly with total number of

visits, with 84% of those with one episode categorized as having LBP

without neurological involvement compared to only 57% of those with

six or more episodes. The other diagnostic categories were LBP with

neurological involvement, LBP caused by congenital lumbar spinal

structural disorders or acquired lumbar spinal structural disorders,

or LBP due to other causes including postoperative issues.

The mean patient age was 51, and 8888 patients-more than half-were

female. Older patients had a significantly higher number of LBP

episodes.

Comorbidities, including diabetes, rheumatoid arthritis,

inflammation, anxiety, depression, asthma/chronic obstructive

pulmonary disease, cardiac disease, gastrointestinal disease,

hypertension, and thyroid disease, were significantly more prevalent

in patients with more LBP episodes.

Nonsteroidal anti-inflammatory drug and opioid usage, calculated

based on prescriptions filled, significantly varied before and after

the initial visit and by the total number of LBP-related visits,

with patients with three to five visits having the largest increase

in usage of NSAIDs, from 31.6% to 48%, and of opioids, from 25.5% to

44.2%.

Medical care usage varied significantly by number of episodes for

all categories measured including the number of hospital inpatient

admissions, admissions for the major diagnostic category of " disease

and disorders of the musculoskeletal system and connective tissue, "

spending less than 24 hours in the emergency department or

observation unit, and outpatient visits for primary care, specialty

care, back pain-specific specialty care, physical or occupational

therapy, mental health, CT/MRI services, and/or spinal x-rays.

However, higher usage did not always correlate with a greater number

of LBP episodes, with primary care visits highest for patients with

two episodes, while specialty, back pain specialty, mental health,

and hospital-based care all increased with higher numbers of LBP

episodes. The likelihood of an inpatient admission following the

initial LBP diagnosis increased with greater age.

Primary care composed the biggest slice of outpatient costs for LBP

patients. Total annual healthcare costs in 2005 dollars for patients

with one episode were $3718, those with two $4805, three to five

$5874, and six or more $6888.