Inflammatory Polyarthritis in the Older Adult

Tara Snelgrove BSc, MSc; Proton Rahman MD, MSc, FRCPC

Disclosures

Geriatrics and Aging. 2006;9(8):544-550. 

In This Article

Rheumatoid Arthritis

Epidemiology

RA is the most common inflammatory arthritis, with an estimated overall prevalence of 1%, which increases to at least 2% in the older population.[3] Females with young-onset RA (RA onset prior to the age of 60) are two to four times as likely to be affected as males. This ratio decreases to 1.5 to 1 for females in late-onset RA (RA onset after the age of 60).[4]

Diagnosis

Diagnosis of RA follows the 1987 American Rheumatism Association criteria. Criteria for RA diagnosis are shown in Table 1 .

Rheumatoid factor is felt to be less useful in diagnosing RA in this population, as the prevalence of autoantibodies increases with age. Anticyclic citrullinated antibody (CCP) may be a more specific marker in the diagnosis of late-onset RA, although this is not readily available in most laboratories.[6]

A major challenge in diagnosing RA in the older population is differentiating it from polymyalgia rheumatica (PMR). Both these entities have overlapping clinical features, especially when PMR presents with peripheral arthritis in the small joints. Furthermore, PMR symptoms can coexist in RA patients, which occurs in about 6.5% of late-onset RA patients.[4] A high degree of suspicion is also required to identify an individual with underlying malignancy, as this is more likely to occur in the later years.

Clinical Signs and Symptoms

The onset of RA can be acute or insidious. Joint destruction is progressive and over time a reduction in range of movement, instability of the joint, malalignment, and deformity can be seen in the affected joint. The pattern of affected joints early in RA is typically symmetric small joint involvement in the hands, feet, and wrist (Figure 2). Later stages of RA progress to involve larger joints, such as the shoulder, elbow, knees, and hip. Cervical spine involvement is also common. However, the lumbar spine is typically not involved. In late-onset RA, there is an increased frequency of shoulder involvement than in early onset RA. However, classical rheumatoid hand deformities of the proximal interphalangeal (PIP), metacarpophalangeal (MCP), and wrist are less likely to be involved.

Figure 2.

Typical joint distribution for rheumatoid arthritis

Extra-articular features of RA include manifestations related to vasculitis (such as rheumatoid nodules, digital infarcts, episcleritis, peripheral neuropathy, palpable purpura or leg ulcers), or due to lymphocytic infiltrate (such as sicca symptoms, hypothyroidism, interstitial lung disease, splenomegaly, or lymphadenopathy).

Late-onset RA patients are more likely to have constitutional symptoms characterized by fatigue, weight loss, myalgia, lymphadenopathy, and PMR symptoms.[4] However, late-onset RA subjects are less likely to have interstitial lung disease and sicca symptoms. It has been suggested that RA is a risk factor for coronary artery disease.[7] Thus it is especially important to monitor older RA patients for cardiac symptoms as they may have comorbid cardiac illness that may be exacerbated.

Laboratory Features

RA is a clinical diagnosis with no one laboratory test to confirm the diagnosis. With respect to nonspecific laboratory features, elevation in erythrocyte sedementation rate and C-reactive protein as well as anemia of chronic disease are more likely to occur with RA in the older population. While the degree of anemia tends to correlate with the activity of underlying RA in younger RA patients, this marker is less helpful in aging adults, who are more prone to anemia from impaired nutritional absorption.

Management

Older patients with RA are best approached with a multidisciplinary team to ensure mobility and independent functional ability as long as possible. Physiotherapy and occupational therapy are key to fall prevention, a major cause of loss of independence in this age group.

The present therapeutic management of RA includes early use of methotrexate (MTX) with rapid escalation of the dose to 20 to 25 mg/week if the response is inadequate (this is generally, but not exclusively, done by specialists). This is usually followed by sequential addition of further disease modifying antirheumatic drugs (DMARDs), i.e., combination therapy (with the addition of DMARDs such as plaquenil, sulfasalazine, azathioprine or leflunomide). Some rheumatologists initiate combination therapy from the outset (usually MTX, plaquenil, and sulfasalazine) at presentation to clinic.

NSAIDs are frequently used for symptomatic relief. A conscious effort is made to minimize the use of corticosteroids. If the combination DMARDs are not successful in controlling the patient's symptoms, antitumour necrosis factor (TNF) agents are then added to the regimen. The anti-TNF agents, which include monoclonal antibodies (infliximab and adalimumab) and receptor antagonists (etanercept), are quite effective in up to 80% of subjects with RA. All the anti-TNF agents appear to be more effective with the use of concomitant MTX therapy.

With respect to pharmacotherapy in the older adult, those receiving NSAIDs are at higher risk of adverse events, especially gastrointestinal bleeding and renal function impairment.[9] These effects are amplified when the patient is taking anticoagulant therapy or diuretics, or has comorbid peptic ulcer or renal disease. NSAIDs have drug-drug interactions with warfarin, beta-blockers, ACE inhibitors, diuretics, phenytoin and digoxin, all of which are commonly used medications in the older population.[10]

DMARD treatment requires close monitoring of renal and hepatic functions, and low doses should be maintained if possible. Methotrexate clearance is correlated with creatinine clearance, and doses must be adjusted in older adults according to renal function. Sulfasalazine has increased risk of gastrointestinal toxicity in this population, and enteric coated tablets should be used.[11]

The biologic agents show great promise in young- and late-onset RA. However, additional care must be exhibited when prescribed to older adults, as their natural infection resistance is lower, and many have been exposed to tuberculosis.

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