Background/Purpose: To perform a systematic review of definitions, risk factors, and outcomes in “generalized osteoarthritis” (GOA).

Methods: We performed a systematic review of Medline literature using the terms osteoarthritis, generalized, polyarticular, multiple joint, multi-joint, and others to obtain articles related to GOA, following PRISMA guidelines.  The search was completed on 9/25/12 by a professional librarian. The initial searches produced 948 articles for title and abstract review (performed by MWS and AEN), after which 108 underwent full text review (AEN and YMG).  Of these, 74, along with 24 identified through bibliographic review of included articles (total=98), were included for data extraction (AEN) based on pre-specified criteria including the requirement for a clearly stated definition of OA (clinical, radiographic, or symptomatic) assessed at more than one body site.

Results: In the 98 included articles, 24 large cohorts (n~30,000) were represented along with numerous clinical series (n~9000), across 22 countries and 60 years (1952-2012).  The sites assessed, and OA definitions at each site, varied widely but most often included the hands and knees. In 30 studies where a definition of GOA was stated, no less than 15 definitions of GOA were given; at least 6 groups used a summed score of joints or radiographic grades at multiple sites (Table).  While interphalangeal joints were almost always included, there was debate about the appropriateness of including other joints such as spine and hip. Estimates of the prevalence of such variably defined GOA ranged from 1-80%, although a majority were in the 5-25% range.

A variety of risk factors and outcomes were considered in the included papers.  Increased risk of GOA or its progression was associated with age, female sex, and genetic/familial factors.  GOA constructs were generally identified more frequently among individuals of European descent.  Associations with increased BMI or other measures of body mass were not consistent across studies. A higher BMD was seen in GOA patients in some series but not others.  One study estimated the heritability of GOA at 42%.  Biomarker (cartilage oligomeric protein [COMP] and urinary type II collagen C-telopeptide [uCTX-II]) levels increased with greater numbers of involved joints.  Increased OA burden was associated with higher mortality, poorer health and function, and increased disability.

Conclusion: While there remains no clear or widely agreed upon definition of GOA, this term is commonly used in the literature.  There remains substantial debate regarding the existence of GOA as a distinct disease entity, and in what populations, although there appears to be a greater impact on health in the presence of OA in more than one joint. It may be more appropriate for individual studies to clearly define joints evaluated and involved with OA, and use alternate, more descriptive terms, such as multi-joint or polyarticular OA.