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14-01-2016 | Quality of life | Review | Article

Patient-reported outcomes in trials of patients with polymyalgia rheumatica: a systematic literature review

Journal:
Rheumatology International

Authors: Annie Huang, Isabel Castrejon

Publisher: Springer Berlin Heidelberg

Abstract

Patient-reported outcomes (PROs) are being increasingly recognized as important measures by rheumatologists. The objective of this review was to evaluate the frequency of use of PROs in studies of patients with polymyalgia rheumatica (PMR). A systematic literature search was performed in PubMed (up to April 2015) to identify any type of clinical studies reporting any type of PROs in patients with PMR. Articles were excluded if they did not include adults with PMR or did not report any PROs. Characteristics of each study such as study design, follow-up, treatment assessed if any, number of patients, mean age, gender, and a description of PROs used were collected to perform a descriptive analysis. From 118 initial studies captured, 28 articles met the predefined criteria, and 20 were finally included in this review. Ten studies (50 %) were randomized clinical trials (RCTs), and 8 (40 %) were cohorts. The most frequently reported domains were: pain (90 %), being the most frequent tool using a visual analogue scale; morning stiffness in minutes (85 %); and function (25 %), evaluated through the Health Assessment Questionnaire. Other domains such as patient global assessment, fatigue, quality of life, and anxiety and depression were infrequently reported. A larger proportion of PROs were included in cohorts in comparison with RCT. Pain and morning stiffness are the most frequently reported PROs. Other domains that may appear relevant for patients are infrequently reported, especially function.

Introduction

Polymyalgia rheumatica (PMR) is a common inflammatory disease of elderly patients, affecting from 0.1 to 0.5 % of over 50- year-olds [ 1]. It is characterized by proximal pain, especially in the shoulder and pelvic girdle, and morning stiffness with high acute-phase reactants, measured by erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP). A “gold standard” test to make the diagnosis is not available. Physicians mainly rely on the clinical picture, and the diagnosis is further supported by a rapid response to glucocorticoids. The initial presentation may mimic other conditions or present with the absence of acute-phase reactants. This heterogeneity may explain the difficulty of diagnosis and a lack of agreement between physicians [ 2]. In addition, a lower acute-phase response does not necessary indicate lesser severity or better prognosis [ 3].
Glucocorticoids are the preferred treatment, leading to a rapid and dramatic improvement, but they may be required for several years in some patients [ 4]. For this reason, PMR is a common indication for long-term steroid use in the community, and it has been associated with serious adverse effects such as diabetes, osteoporosis, and infections [ 5].
Although a rapid resolution of symptoms after treatment is a diagnostic hallmark, there is no consensus on what constitutes an appropriate response and which outcomes should be monitored. The lack of reliable and sensitive measures to evaluate disease activity and the lack of standardized classification criteria to identify patients with PMR may explain why the evidence for efficacy of any treatment different to glucocorticoids remains limited [ 6].
Current clinical guidelines recommend monitoring patients treated for PMR on the basis of symptoms since, as we previously noted, conventional inflammatory markers can be misleading [ 6]. Reliable and comparable outcomes are required not only to balance the benefits and adverse events of a long-term steroid therapy, but also to investigate the potential use of other drugs such as corticosteroid-sparing agents.
Patient-reported outcomes (PROs), defined as outcomes that are completed by patients, have been increasingly recognized as important measures over the past few years by rheumatologists. They incorporate the patient’s perspective of the disease capturing the impact of the disease in patient’s lives, and they perform well in assessing disease activity in patients with PMR [ 7]. Different PROs such as pain, morning stiffness, or physical function have been proposed as recommended outcome measures to be used in practice and clinical trials [ 8]. In addition, most remission or flare definitions include at least one self-reported variable from the medical history [ 9].
The goal of this study was to review the frequency of use of PROs in published studies including randomized controlled trials and cohorts of PMR through a systematic literature review.

Materials and methods

To obtain all published articles reporting any type of PROs in PMR, the literature search was performed in PubMed database on April 13, 2015. Publications were identified using the following MeSH term: “polymyalgia rheumatica” with a limitation to “English” and “clinical trials.” Inclusion criteria comprised articles reporting any type of clinical design, patients with PMR, and including at least the evaluation of any PRO measure. Articles were excluded if they did not concern PMR or if they did not focus on PROs. Editorials and letters were also excluded to provide an overview of the use of PROs in original research articles. A first screening was performed based on titles and abstracts of the articles by AH and IC. The articles fulfilling the inclusion criteria were retrieved for a full paper review.
Data were obtained on year of publication, study design (RCT, prospective cohort), follow-up, number and characteristics of patients, treatment under evaluation, and PROs included. A description of the articles reporting PROs is presented as a table.
All information about PROs was collected, including composite indices, which included at least one PRO, and then classified into domains. Results are presented as frequency of reported domains and frequency of tools to evaluate each domain in RCTs and cohorts as a descriptive analysis.

Results

Of the 118 publications identified by the literature search, 28 were selected for full review and 20 finally included in the analysis. Ninety publications were excluded after screening of title and abstract (Fig.  1).
The characteristics of the included publications are given in Table  1 in chronological order. Of the 20 publications, 10 (50 %) were RCTs, 8 (40 %) were prospective cohorts, 1 (5 %) was a case control, and 1 (5 %) was a pilot observational study. Patients’ characteristics were typical of PMR populations, with a mean age ranging from 62.5 to 76.6 and female gender ranging from 50 to 90.7 %. Number of patients included ranged from 6 to 213. In 13 (65 %) of these articles, different glucocorticoid regimes or other drugs such as corticosteroid-sparing agents were evaluated. The remaining 7 (35 %) studies evaluated predictors of vertebral fractures, the impact of PMR on clinical outcomes, gender differences in PMR patients, laboratory measures to identify relapse, diagnostic, and response criteria.
Table 1
Characteristics of the 20 included studies
References
Type of study
Participants
PROs included
Comments
Mackie et al. [ 8]
OMERACT initiative to develop a core set of outcomes measures
104 PMR patients
Mean age: NA
Female gender: NA
Outcomes of importance to patients: pain, stiffness, function (HAQ), fatigue, anxiety and depression
Stiffness emerged as an important outcome for patients but requires proper wording
Matteson et al. [ 7]
Prospective cohort
Follow-up: 26 weeks
Rx: 15 mg PDN tapered gradually
85 new-onset PMR patients
Mean age: 72.6
Female gender: 60 %
Global pain (VAS 100-mm); Fatigue (VAS 100-mm); MS (minutes) last 24 h; Functional Status (MDHAQ); Quality of life (SF-36)
Authors propose a minimum set of PROs to be used in practice and CT: pain, hip pain, MS, physical function, and mental function
Cimmino et al. [ 34]
Prospective cohort
Follow-up: 4 weeks
Rx: 12.5 mg PDN
60 PMR patients
Mean age: 71.4
Female gender: 58 %
Global pain (VAS 0–10)
Fatigue (VAS 0–10)
MS (minutes)
Neither MS nor fatigue differentiates between responders and non-responders
Kreiner and Galbo [ 24]
RCT
Follow-up: 14 days
Rx: Etanercept
20 GC-naïve PMR patients
Mean age: 71.4–72.6
Female gender: 60–70 %
Global pain (VAS 10-cm)
MS (minutes)
Primary outcome was change in PMR activity score which includes these PROs
Calvo et al. [ 26]
Case control
Follow-up: 1 year
20 patients with PMR (10 vertebral fracture)
Mean age: 75.6–76.6
Female gender: 50 %
Global pain (VAS)
Authors conclude that vertebral fractures could be predicted by VAS pain
Salvarani et al. [ 35]
Multicenter RCT
Follow-up: 52 weeks
Rx: infliximab + PDN versus placebo + PDN
51 PMR patients
Mean age: 70.7–70.9
Female gender: 54–70 %
Function (HAQ)
HAQ was not evaluated as a secondary endpoint
Hutchings et al. [ 30]
Multicenter prospective study to evaluate impact of PMR on clinical outcomes
Follow-up: 12 months
129 PMR patients
Mean age: 70.9
Female gender: 59.7 %
Proximal pain (shoulders and pelvic girdle) on a VAS
MS (minutes)
Function (HAQ)
Physical/mental SF-36 components
Authors conclude that disease monitoring should include inflammatory symptoms and no acute-phase markers alone
Catanoso et al. [ 36]
Cohort
Follow-up: 36 weeks
Rx: Etanercept
6 Patients with refractory PMR
Mean age: 75
Female gender: 83 %
Pain (VAS 10-cm)
MS (minutes)
Function (HAQ)
PATGL (VAS 10-cm)
Leeb’s DAS is calculated
Cimmino et al. [ 25]
Prospective cohort
Follow-up: 15 months
80 PMR patients
Mean age: 67.6–70.6
Female gender: 65 %
Pain (VAS 100-mm)
MS (minutes)
Gender comparison
Salvarani et al. [ 37]
Prospective cohort
Follow-up: 39 months
94 PMR patients
Mean age: 74
Female gender: 74.5 %
MS (minutes)
Lab measures useful to identify relapse. MS not evaluated
Bird et al. [ 38]
Multisite cohort
Cross-sectional
213 PMR patients
Mean age: NA
Female gender: NA
Evaluation on pain
MS > 1 h (yes/no)
Evaluation of different diagnostic criteria sets
Leeb et al. [ 17]
Large international cohort: EULAR response criteria
76 PMR patients
Mean age: 68.7
Female gender: 90.7 %
Pain (VAS 100-mm)
MS (min)
Patient assessment (VAS 100-mm)
In the proposed core set of response criteria, pain was the only one obligatory
Salvarani et al. [ 23]
RCT
Follow-up: 7 months
Rx: MP shoulder injection versus placebo
20 PMR patients
Mean age: 70–71
Female gender: 60–80 %
MS (min)
Pain (VAS 10-cm)
Patient assessment (VAS 10-cm)
A dramatic reduction in pain was seen from the first injection
Dasgupta et al. [ 39]
RCT
Follow-up: 12 weeks
Rx: im MP versus oral GC
60 PMR patients
Mean age: 69.8–71.9
Female gender: 70–73 %
Early MS (min, 4 grades)
Pain (VAS 10-cm)
Remission definition includes VAS pain
Van Der Veen et al. [ 40]
RCT
Follow-up: 2 years
Rx: MTX versus placebo
40 PMR patients
Mean age: 70.9
Female gender: 75 %
Muscle pain (yes/no)
MS (yes/no)
PROs not include it in the disease activity evaluation
Krogsgaard et al. [ 41]
RCT
Follow-up: 12 months
Rx: prednisolone versus DFZ
30 PMR patients
Mean age: 72.5–75
Female gender: 56.3–71.4 %
Muscle pain and MS in a 0–3 scale
Evaluation of effect of RX in bone mineralization
Krogsgaard et al. [ 22]
RCT
Follow-up: 12 months
Rx: prednisolone versus DFZ
30 PMR patients
Mean age: 72.5–75
Female gender: 56.3–71.4 %
Muscle pain and MS in a 0–3 scale
Evaluation of disease activity through these PROs
Di Munno et al. [ 21]
RCT
Follow-up: 6 weeks
Rx: DFZ versus 6-MP
31 PMR patients
Mean age: 62.5–66.6
Female gender: 66.7–71.4 %
Pain (VAS 10-cm)
Early MS
Satisfactory response defined as 50 % reduction in pain and MS
Di Munno et al. [ 20]
RCT
Follow-up: 9 months
Rx: Vit D versus placebo
24 PMR patients
Mean age: 67.9
Female gender: 62.5 %
Subjective pain from 0 to 4
Pain was used to compare both treatment groups
Lund et al. [ 19]
Cross-over RCT
Follow-up: 2 weeks
Rx: DFZ versus PDN
41 PMR patients
Mean age: 73
Female gender: 78 %
MS (0–3)
Pain (0–3)
Pain and MS were used to compare both treatment groups
PROs patient-reported outcomes, PMR polymyalgia rheumatica, MS morning stiffness, RCT randomized clinical trial, GC glucocorticoids, PDN prednisone, MP methylprednisolone, MTX methotrexate, GCA giant cell arteritis, DFZ deflazacort
Seven domains were reported in the 20 articles: pain, morning stiffness, function, patient global assessment, fatigue, quality of life, and anxiety and depression (Table  2).
Table 2
PROs evaluated in recent studies of PMR patients
Domains
Tools
Total studies ( n = 20)
RCTs ( n = 10)
Cohorts ( n = 8)
Pain
Frequency of domain
18 (90 %)
9 (90 %)
7 (87.5 %)
 Pain on a VAS
11 (61 %)
4 (44 %)
6 (86 %)
 Muscle pain (yes/no)
1 (6 %)
1 (11 %)
0 (0 %)
 Muscle pain (0–3)
3 (17 %)
3 (33 %)
0 (0 %)
 Subjective pain (0–4)
1 (6 %)
1 (11 %)
0 (0 %)
 Not specified
2 (11 %)
0 (0 %)
1 (14 %)
Morning stiffness
Frequency of domain
17 (85 %)
8 (80 %)
8 (100 %)
 MS in minutes
9 (53 %)
2 (25 %)
7 (88 %)
 MS in 4 grades
1 (6 %)
1 (13 %)
0 (0 %)
 MS (yes/no)
2 (12 %)
1 (13 %)
1 (13 %)
 MS (0–3)
3 (18 %)
3 (38 %)
0 (0 %)
 Not specified
2 (12 %)
1 (13 %)
0 (0 %)
Function
Frequency of domain
5 (25 %)
1 (10 %)
3 (37.5 %)
 HAQ
4 (80 %)
1 (100 %)
2 (67 %)
 MDHAQ
1 (20 %)
0 (0 %)
1 (33 %)
Patient global assessment
Frequency of domain
3 (15 %)
1 (10 %)
2 (25 %)
 VAS
3 (100 %)
1 (100 %)
2 (100 %)
Fatigue
Frequency of domain
3 (15 %)
0 (0 %)
2 (25 %)
 Fatigue on a VAS
2 (67 %)
0 (0 %)
2 (100 %)
 Not specified
1 (33 %)
0 (0 %)
0 (0 %)
Quality of life
Frequency of domain
2 (10 %)
0 (0 %)
2 (25 %)
 SF-36
2 (100 %)
0 (0 %)
2 (100 %)
Anxiety and depression
Frequency of domain
1 (5 %)
0 (0 %)
0 (0 %)

Pain

Pain was recorded as an outcome in 18 (90 %) of these studies. It was the most frequent PRO collected in RCT and cohorts. The majority of studies ( n = 11, 61 %) used a visual analogue scale (VAS) to evaluate pain with no defined stem anchors, and the remainder used different grades or the presence versus absence of pain.

Morning stiffness

Morning stiffness was recorded in 17 (85 %), with no consistency about how this was defined or collected. It was most frequently evaluated by morning stiffness duration in minutes without any grades ( n = 9, 53 %); some studies graded morning stiffness from 0 to 3 or 4, and two studies only evaluated the presence or absence of morning stiffness.

Function

Function was only reported in 25 % of the studies, more frequently in cohorts than in RCT. The most frequent tool for this domain was the Health Assessment Questionnaire (HAQ) [ 10], and the remaining studies used the modified HAQ (MHAQ) [ 11], which is a modified shorter version of the original HAQ. Both are self-reported questionnaires developed initially for rheumatoid arthritis (RA) that comprise eight categories of functioning including dressing, rising, eating, walking, self-hygiene, and other daily activities.

Other domains

Patient global assessment was only reported in three studies (15 %), in one RCT and in two cohorts using a VAS in all of these studies. Fatigue was also reported only in three studies using a VAS; none of them were RCT. Other less frequently reported domains were quality of life, and anxiety and depression. Quality of life was assessed using a generic form, the Short-Form Health Survey (SF-36), which contains 36 questions measuring health across eight physical and psychological dimensions [ 12]. Anxiety and depression were only included in a study to evaluate outcomes of importance to patients without any specific information about how to measure these two domains [ 8].

Discussion

Only eight domains reflecting patient-reported outcomes were found in this review including trials of patients with PMR. The two domains most frequently reported were pain and morning stiffness.
Pain is a very important symptom for PMR patients, and it has been included in each set of diagnosis criteria proposed since the first one by Bird and Wood in 1979 [ 1316]. Pain has also been shown to be important to evaluate response to therapy. In 2003, the European Collaborating PMR group proposed the first response criteria for PMR based on a core set of five variables [ 17]. Pain on a VAS was selected as the central measure for disease activity being the only one mandatory in this core set. The selection was based on the dominant role of pain in patients’ symptoms and has proved sensitivity to change. Morning stiffness was also included in this response criteria core set with CRP, elevation of upper limbs, and the doctor’s global assessment, but only a change in three of these four is required to reflect a change in disease activity. Having two PROs included in a set of only five variables for response highlights the importance of patient self-evaluation in PMR. In addition, based on this core set and in analogy with a simplified disease activity index (SDAI) for rheumatoid arthritis (RA), a disease activity index for PMR has been proposed [ 18]. This composite index, the PMR activity score (PMR-AS), includes pain on a VAS and morning stiffness in minutes multiplied by 0.1 to avoid a high weighting of this specific symptom. PMR-AS shows a high correlation not only with patient’s global assessment, but also with patient satisfaction. Using this composite index helps describe the clinical situation and adds feasibility. Having a score as an absolute number also helps comparing patients much more easily.
In the majority of the studies included in this review, pain was recorded on a VAS referring mainly to proximal pain in the shoulder or pelvic girdle. In some studies, pain was evaluated as an outcome to compare treatment groups [ 1924], or to evaluate disease activity differences according to gender [ 25], or as a potential predictor of vertebral fractures [ 26].
Morning stiffness was the second most reported PRO in this review mainly evaluated by duration but with no consistency about how this was defined or collected. Morning stiffness is considered an important diagnostic clue in PMR, but it is difficult to measure accurately especially when using duration of morning stiffness that has been reported to show poor test–retest reliability in PMR [ 7]. A possible explanation for this poor test–retest could be the fluctuation of this symptom during the day. From the patient’s perspective, morning stiffness has been defined as a restriction of movement or better described as what it has prevented them from doing. From patient experience, morning stiffness is less responsive to glucocorticoids in comparison with pain [ 27]. Morning stiffness has also been included in different diagnostic criteria—lasting for more than 1 h [ 13, 14], as part of the response criteria previously described [ 17], and in the PMR-AS [ 18].
The two PROs included in most of the diagnostic criteria were also the most frequently reported in clinical trials: pain and morning stiffness. The evaluation of pain has been included in each one of these criteria as pain/aching or tenderness in shoulder or pelvic girdle area, in shoulders, upper arm, hips or pelvis, and thighs reflecting how pain is experienced by the patients in the course of the disease. Pain is an overwhelming symptom for patients always part of the clinical picture. Although it is often not well localized, it tends to be more responsive to medication in comparison with other symptoms [ 27]. This may explain why it is also included as an outcome in most clinical trials. In contrast, morning stiffness was included only in three of these diagnostic criteria and reported less frequently in clinical trials. It is also considered an important diagnostic clue in PMR but more difficult to evaluate and poorly responsive to treatment.
Function through HAQ or MHAQ was only reported in the 25 % of the articles. This is a surprisingly low percentage having taken into account that both are generic instruments that can be used in any rheumatic diagnosis [ 28]. Function correlates with other measures of disease activity in PMR and is responsive to change [ 29, 30]. Moreover, function is a strong predictor of mortality not only in patients with RA [ 31], but also in the general population [ 32]. For patients with PMR, being able to perform common activities of daily living was described as the most important aspect of their disease that would indirectly reflect their morning stiffness [ 27].
Other domains such as patient global assessment, fatigue, quality of life, and anxiety and depression were infrequently reported, though they appear important from the patient’s point of view [ 8].
Pain, function, and patient global are part of an established core set of PROs used across most rheumatic diseases [ 33]. It is surprising that only pain is a well-established PRO in PMR patients. A possible explanation is that in contrast with other rheumatic diseases, the typical increase in ESR (40 mm/h or more) and CRP plus the prompt response of symptoms to low-dose glucocorticoids seen in PMR patients may facilitate the monitoring of the disease activity. Laboratory data and response to treatment may be considered as more objective outcomes compared to PROs for most rheumatologists explaining why other PROs would not be included in these clinical trials.
A limitation for this study is that only PubMed was consulted during the search; no other databases such as EMBASE or the Cochrane Library were reviewed. This may limit the exhaustiveness of the actual review but give a reasonable overview regarding use of PROs.
Thus, in conclusion, although PROs can be useful for better monitoring of disease activity and evaluating treatment response in PMR, only pain on a VAS is systematically included. While morning stiffness is an important symptom for patients, there is no consistency about how it should be measured. In addition, no PROs have been defined yet for PMR as part of a core set in the rheumatology community. An OMERACT special interest group is working toward the development of a core set of outcomes for PMR. Although several PROs have been identified to be of importance, such as pain, stiffness, fatigue, sleep disturbance, function, and anxiety and depression, further validation work is still in progress [ 33]. Additional work is also needed to obtain a better insight of which outcomes should be necessary to incorporate the patient’s perspective.

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