PHARMACOTHERAPY PRINCIPLES AND PRACTICE CARE PLANS & CASES
Upon completion of the chapter, the reader will be able to:
Explain the pathophysiologic mechanisms involved in the development of osteoarthritis (OA).
Identify risk factors associated with OA.
Recognize the clinical presentation of OA.
Determine the goals of therapy for individual patients with OA.
Formulate a rational nonpharmacologic plan for patients with OA.
Recommend a pharmacologic plan for treating OA, taking into consideration patient-specific factors.
Develop monitoring parameters to assess effectiveness and adverse effects of pharmacotherapy for OA.
Modify an unsuccessful treatment strategy for OA.
Deliver effective patient counseling, including lifestyle modifications and drug therapy, to facilitate effective and safe management of OA.
KEY CONCEPT Osteoarthritis (OA) is the most common form of arthritis and is strongly related to age. Its incidence and cost of care will increase dramatically in the coming years due to a burgeoning senior citizenry. Weight-bearing joints (eg, hips and knees) are most susceptible, but non–weight-bearing joints, especially the hands, also may be involved. Because of its high prevalence and involvement of joints critical for daily functioning, the disease causes tremendous morbidity and financial burden.1 OA is the leading cause of chronic mobility disability and the most common reason for total-hip and total-knee replacement.2
EPIDEMIOLOGY AND ETIOLOGY
Globally, the age-standardized prevalence of knee and hip OA is at least 3.8% and 0.85%, respectively. High-income countries, which generally have older populations, have a higher prevalence than low-income countries.3 The National Arthritis Data Workgroup estimates that 27 million Americans have signs and symptoms of OA.4 Approximately 7% of US adults have daily symptomatic hand OA, whereas 6% and 3% report daily symptoms affecting the knees and hips, respectively.4 After age 60, 10% to 17% of persons report such symptoms.4
The prevalence of OA is greater in women by 1.5- to 2-fold, and they tend to have more generalized disease. Women are also more likely to have inflammation of the proximal and distal interphalangeal joints of the hands, which manifest as Bouchard nodes and Heberden nodes, respectively. OA of the hip occurs more frequently in men.
The prevalence of OA in whites is similar to that in African Americans, but the latter may experience more severe and disabling disease. Persons of Chinese descent rarely have hip OA; they also are less likely to develop hand OA but more likely to develop knee OA.
OA is characterized by damage to diarthrodial joints and joint structures (Figure 58–1). The pathophysiology is multifactorial and typified by progressive destruction of joint cartilage, erratic new bone formation, thickening of subchondral bone and the joint capsule, bony remodeling, development of osteophytes, variable degrees of mild synovitis, ...