Effect of Disease-Modifying Anti-Rheumatic Drugs on Bone Structure and Strength in Psoriatic Arthritis Patients

David Simon; Arnd Kleyer; Sara Bayat; Koray Tascilar; Eleni Kampylafka; Timo Meinderink; Louis Schuster; Ramona Petrov; Anna-Maria Liphardt; Juergen Rech; Georg Schett; Axel J. Hueber

Disclosures

Arthritis Res Ther. 2019;21(162) 

In This Article

Abstract and Introduction

Abstract

Objectives: To address whether the use of methotrexate (MTX) and biological disease-modifying anti-rheumatic drugs (bDMARDs) impacts bone structure and biomechanical properties in patients with psoriatic arthritis (PsA).

Methods: This is a cross-sectional study in PsA patients receiving no DMARDs, MTX, or bDMARDs. Volumetric bone mineral densities (vBMDs), microstructural parameters, and biomechanical properties (stiffness/failure load) were determined by high-resolution peripheral quantitative CT and micro-finite element analysis in the respective groups. Bone parameters were compared between PsA patients with no DMARDs and those receiving any DMARDs, MTX, or bDMARDs, respectively.

Results: One hundred sixty-five PsA patients were analyzed, 79 received no DMARDs, 86 received DMARDs, of them 52 bDMARDs (TNF, IL-17- or IL-12/23 inhibitors) and 34 MTX. Groups were balanced for age, sex, comorbidities, functional index, and bone-active therapy, while disease duration was longest in the bDMARD group (7.8 ± 7.4 years), followed by the MTX group (4.6 ± 7.4) and the no-DMARD group (2.9 ± 5.2). No difference in bone parameters was found between the no-DMARD group and the MTX group. In contrast, the bDMARD group revealed significantly higher total (p = 0.001) and trabecular vBMD (p = 0.005) as well as failure load (p = 0.012) and stiffness (p = 0.012). In regression models, age and bDMARDs influenced total vBMD, while age, sex, and bDMARDs influenced failure load and stiffness.

Conclusion: Despite longer disease duration, bDMARD-treated PsA patients benefit from higher bone mass and better bone strength than PsA patients receiving MTX or no DMARDs. These data support the concept of better control of PsA-related bone disease by bDMARDs.

Introduction

Psoriatic arthritis (PsA) is a chronic inflammatory joint disease associated with psoriasis characterized by peripheral arthritis and enthesitis leading to structural damage.[1–3] Bone erosions and enthesiophytes are hallmarks of local structural damage in PsA. More recently, the impact of PsA on systemic bone is increasingly appreciated. Hence, systemic bone loss has been documented to occur in PsA[4,5] and increased prevalence of fractures in PsA patients is reported.[6]

In contrast to RA, little is known about the effect of disease-modifying anti-rheumatic drugs (DMARDs) on bone structure in PsA. In rheumatoid arthritis (RA), biological DMARDs (bDMARDs) have shown to inhibit bone loss and thus may prevent pathological fractures.[7–9] To date, no such studies have been done in PsA; however, it can be assumed that effective control of inflammation may also impact secondary bone loss and bone biomechanics in PsA patients. In support of this notion, bDMARD treatment in PsA patients retards the progression of periarticular bone erosions[10–12] and periarticular bone loss.[13–15] Whether systemic bone mass and bone biomechanical properties are influenced by DMARD treatment is unclear to date. Furthermore, methotrexate treatment may not necessarily share potential beneficial effects of bDMARDs on bone in PsA patients.

While dual-energy X-ray absorptiometry (DXA) or digital X-ray radiogrammetry (DXR) can quantify bone loss, they do not allow separate assessment of changes in the cortical and trabecular bone compartment or the biomechanical properties of bone. High-resolution peripheral quantitative CT (HR-pQCT) enables the analysis of bone mass and microstructure and via integration of micro-finite element analysis (μFEA) the assessment of bone strength.[16] An HR-pQCT study in RA patients has already shown that the biomechanical properties of the bone are reduced in RA patients.[17]

To investigate whether DMARD treatment influences systemic bone structure and function in PsA patients, we investigated bone density, bone microstructure, and biomechanical properties in patients receiving either no DMARDs, methotrexate (MTX) treatment, or biologic DMARDs (bDMARDs) by HR-pQCT. In this cross-sectional study, we were specifically interested, whether PsA patients treated with either MTX or bDMARDs show a better bone structure and function than PsA patients receiving no DMARDs.

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