Genome-wide association study identifies variants at CSF1, OPTN and TNFRSF11A as genetic risk factors for Paget's disease of bone.

Paget's disease of bone (PDB) is a common disorder with a strong genetic component characterized by focal increases in bone turnover, which in some cases is caused by mutations in SQSTM1. To identify additional susceptibility genes, we performed a genome-wide association study in 750 individuals with PDB (cases) without SQSTM1 mutations and 1,002 controls and identified three candidate disease loci, which were then replicated in an independent set of 500 cases and 535 controls. The strongest signal was with rs484959 on 1p13 near the CSF1 gene (P = 5.38 x 10(-24)). Significant associations were also observed with rs1561570 on 10p13 within the OPTN gene (P = 6.09 x 10(-13)) and with rs3018362 on 18q21 near the TNFRSF11A gene (P = 5.27 x 10(-13)). These studies provide new insights into the pathogenesis of PDB and identify OPTN, CSF1 and TNFRSF11A as candidate genes for disease susceptibility.

Mutations of SQSTM1 are associated with severity and clinical outcome in paget disease of bone.

Paget disease of bone (PDB) is a common disorder characterized by increased bone turnover at one of more sites throughout the skeleton. Genetic factors play an important role in the pathogenesis of PDB, and the most important predisposing gene is SQSTM1, which is mutated in about 10% of patients. Here we investigated the relationship between SQSTM1 mutation status, disease severity, and clinical outcome in 737 patients who took part in a randomized study of two different management strategies for the disease. Mutations of SQSTM1 were detected in 80 of 737 (10.9%) patients. Mutation carriers had an earlier age at diagnosis (59.4 ± 11.5 versus 65.0 ± 10.4 years, p < .0001) and a greater number of affected bones (3.2 ± 1.2 versus 2.1 ± 1.2, p < .001) and more commonly required orthopedic surgery (26.2% versus 16.1%, p = .024) and bisphosphonate therapy (86.3% versus 75.2%, p = .01) than those without mutations. Quality of life, as assessed by the short-form-36 (SF36) physical summary score, was significantly reduced in carriers (34.0 ± 11.3 versus 37.1 ± 11.4, p = .036). During the study, fractures were more common in carriers (12.5% versus 5.3%, p = .011), although most of these occurred in unaffected bone. This study demonstrates that SQSTM1 mutations are strongly associated with disease severity and complications of PDB. Genetic testing for SQSTM1 mutations may be of value in identifying individuals at risk of developing severe disease, but further studies will be required to determine if a program of genetic testing and early intervention in these individuals would be cost-effective or be of benefit in preventing these complications.

Randomized trial of intensive bisphosphonate treatment versus symptomatic management in Paget's disease of bone.

Bisphosphonates are widely regarded as the treatment of choice for Paget's disease of bone (PDB) because of their potent inhibitory effects on bone turnover, but the effects of bisphosphonate therapy on symptoms and complications of PDB have been little studied. Here we report the results of a randomized trial that compared the effects of symptomatic treatment with intensive bisphosphonate therapy in a cohort of 1324 patients with PDB who were followed up for a median of 3 years (range 2 to 5 years). The symptomatic treatment group was treated only if they had pagetic bone pain, for which they were first given analgesics or anti-inflammatory drugs, followed by bisphosphonates if they did not respond. The intensive group received repeat courses of bisphosphonates irrespective of symptoms with the aim of reducing and maintaining serum alkaline phosphatase (ALP) levels within the normal range. The endpoints were fracture, orthopedic surgery, quality of life, bone pain, and hearing thresholds. Serum ALP levels were significantly lower in the intensive treatment group than in with the symptomatic treatment group within 4 months of commencing treatment and remained lower throughout the study (p < .001). There was no difference between the groups in quality of life (as assessed by the SF36 questionnaire), in overall bodily pain, or in pagetic bone pain. Hearing thresholds, as assessed by audiometry did not change significantly and did not differ between the treatment groups. Clinical fractures occurred in 46 of 661 patients (7.0%) in the intensive treatment group compared with 49 of 663 patients (7.4%) in the symptomatic treatment group, and orthopedic surgery was required in 50 of 661 patients (7.3%) in the intensive treatment group and in 55 of 663 patients (8.3%) in the symptomatic treatment group. These differences were not significant. Subgroup analyses of patients with elevated ALP levels at baseline and those who did or did not receive bisphosphonates during the study yielded similar results to those in the study group as a whole. We conclude that striving to maintain normal ALP levels with intensive bisphosphonate therapy confers no clinical advantage over symptom-driven management in patients with established PDB. Neither management strategy had a significant beneficial impact on pain or quality of life (Clinical trial registration number ISRCTN12989577).

Meaning behind measurement: self-comparisons affect responses to health-related quality of life questionnaires.

PURPOSE: The subjective nature of quality of life is particularly pertinent to the domain of health-related quality of life (HRQOL) research. The extent to which participants' responses are affected by subjective information and personal reference frames is unknown. This study investigated how an elderly population living with a chronic metabolic bone disorder evaluated self-reported quality of life. METHODS: Participants (n = 1,331) in a multi-centre randomised controlled trial for the treatment of Paget's disease completed annual HRQOL questionnaires, including the SF-36, EQ-5D and HAQ. Supplementary questions were added to reveal implicit reference frames used when making HRQOL evaluations. Twenty-one participants (11 male, 10 female, aged 59-91 years) were interviewed retrospectively about their responses to the supplementary questions, using cognitive interviewing techniques and semi-structured topic guides. RESULTS: The interviews revealed that participants used complex and interconnected reference frames to promote response shift when making quality of life evaluations. The choice of reference frame often reflected external factors unrelated to individual health. Many participants also stated that they were unclear whether to report general or disease-related HRQOL. CONCLUSIONS: It is important, especially in clinical trials, to provide instructions clarifying whether 'quality of life' refers to disease-related HRQOL. Information on self-comparison reference frames is necessary for the interpretation of responses to questions about HRQOL.

Pathogenesis and management of Paget's disease of bone.

Paget's disease of bone is a common disease characterised by focal areas of increased bone turnover, affecting one or several bones throughout the skeleton. Paget's disease is often asymptomatic but can be associated with bone pain and other complications such as osteoarthritis, pathological fracture, bone deformity, deafness, and nerve compression syndromes. Genetic factors have an important role in this disease, and mutations have been identified in four genes that cause Paget's disease and related syndromes. The most important of these is Sequestosome 1 (SQSTM1), which is a scaffold protein in the nuclear factor kappaB (NFkappaB) signalling pathway. Patients with SQSTM1 mutations have severe Paget's disease of bone and a high degree of penetrance with increasing age. Environmental factors also contribute. Most research has focused on paramyxovirus infection as a possible trigger, but evidence for this notion is conflicting. Other potential triggers include deficiency of dietary calcium and repetitive mechanical loading of the skeleton. Medical management of Paget's disease of bone is based on giving inhibitors of osteoclastic bone resorption, and bisphosphonates are the treatment of first choice. Bisphosphonate therapy is primarily indicated for patients who have bone pain arising from increased metabolic activity in affected bones. Bisphosphonate therapy is highly effective at reducing bone turnover, and it has been shown to heal radiological lesions and restore normal histology; however, the long-term effects of bisphosphonates on disease progression have not been adequately studied. No firm evidence as yet exists to show that bisphosphonates can prevent the development of complications of Paget's disease of bone, and further work is needed to address the effects of treatment on long-term clinical outcome.

Protocol for stage 2 of the GaP study (genetic testing acceptability for Paget's disease of bone): a questionnaire study to investigate whether relatives of people with Paget's disease would accept genetic testing and preventive treatment if they were available.

BACKGROUND: Paget's disease of bone (PDB) disrupts normal bone architecture and causes pain, deformity, deafness, osteoarthritis, and fractures. Genetic factors play a role in PDB and genetic tests are now conducted for research purposes. It is thus timely to investigate the potential for a clinical programme of genetic testing and preventative treatment for people who have a family history of PDB. This study examines the beliefs of relatives of people with PDB. It focuses particularly on illness and treatment representations as predictors of the acceptability and uptake of potential clinical programmes. Illness representations are examined using Leventhal's Common Sense Self-Regulation Model while cognitions about treatment behaviours (acceptance of testing and treatment uptake) are conceptualised within the Theory of Planned Behaviour. METHODS/DESIGN: A postal questionnaire of non-affected relatives of people with Paget's disease. The sample will include relatives of Paget's patients with a family history of Paget's disease and relatives of Paget's patients without a family history of Paget's disease. The questionnaire will explore whether a range of factors relate to acceptability of a programme of genetic testing and preventive treatment in relatives of Paget's disease sufferers. The questionnaire will include several measures: illness representations (as measured by the Brief Illness Perceptions Questionnaire); treatment representations (as measured by Theory of Planned Behaviour-based question items, informed by a prior interview elicitation study); descriptive and demographic details; and questions exploring family environment and beliefs of other important people. Data will also be collected from family members who have been diagnosed with Paget's disease to describe the disease presentation and its distribution within a family. DISCUSSION: The answers to these measures will inform the feasibility of a programme of genetic testing and preventive treatment for individuals who are at a high risk of developing Paget's disease because they carry an appropriate genetic mutation. They will also contribute to theoretical and empirical approaches to predicting diagnostic and treatment behaviours from the combined theoretical models.

Implicit self-comparisons against others could bias quality of life assessments.

OBJECTIVES: To explore how patient-reported health-related quality of life (HRQL) and global health status are affected by use of differing personal reference frames. We hypothesized that implicit comparisons against self at an earlier time, against healthy peers, or against ill patients would greatly affect patients' response values. STUDY DESIGN AND SETTING: Patients in a randomized trial for treatment of Paget's disease completed annual HRQL questionnaires. Supplementary questions were appended, asking the patients whether they were aware of having made implicit comparisons. RESULTS: The majority of patients reported considering themselves a year ago (31% at baseline), themselves before becoming ill (23%), or other healthy people (24%), with similar proportions during follow-up. Mean HRQL scores varied substantially according to the declared frame of reference, with differences as big as 19% of the scale score, or a standardized mean effect size of 0.74 standard deviations. CONCLUSION: Reported reference frames were associated with effects of similar magnitude to the differences in HRQL that are regarded as clinically important. This may be of particular concern in trials that randomize patients to management in different settings, such as treatment at home/in hospital, or surgery/chemotherapy and might bias or obscure HRQL differences.

Protocol for stage 1 of the GaP study (Genetic testing acceptability for Paget's disease of bone): an interview study about genetic testing and preventive treatment: would relatives of people with Paget's disease want testing and treatment if they were available?

BACKGROUND: Paget's disease of bone (PDB) is characterised by focal increases in bone turnover, affecting one or more bones throughout the skeleton. This disrupts normal bone architecture and causes pain, deformity, deafness, osteoarthritis, and fractures. Genetic factors are recognised to play a role in PDB and it is now possible to carry out genetic tests for research. In view of this, it is timely to investigate the clinical potential for a programme of genetic testing and preventative treatment for people who have a family history of PDB, to prevent or delay the development of PDB. Evidence from non-genetic conditions, that have effective treatments, demonstrates that patients' beliefs may affect the acceptability and uptake of treatment. Two groups of beliefs (illness and treatment representations) are likely to be influential. Illness representations describe how people see their illness, as outlined in Leventhal's Self-Regulation Model. Treatment representations describe how people perceive potential treatment for their disease. People offered a programme of genetic testing and treatment will develop their own treatment representations based on what is offered, but the beliefs rather than the objective programme of treatment are likely to determine their willingness to participate. The Theory of Planned Behaviour is a theoretical model that predicts behaviours from people's beliefs about the consequences, social pressures and perceived control over the behaviour, including uptake of treatment. METHODS/DESIGN: This study aims to examine the acceptability of genetic testing, followed by preventative treatment, to relatives of people with PDB. We aim to interview people with Paget's disease, and their families, from the UK. Our research questions are:1. What do individuals with Paget's disease think would influence the involvement of their relatives in a programme of genetic testing and preventative treatment? What do relatives of Paget's disease sufferers think would influence them in accepting an offer of a programme of genetic testing and preventative treatment? DISCUSSION: Our research will be informed by relevant psychological theory: primarily the Self-Regulation Model and the Theory of Planned Behaviour. The results of these interviews will inform the development of a separate questionnaire-based study to explore these research questions in greater detail.

An integrated approach to consumer representation and involvement in a multicentre randomized controlled trial.

Although, consumer involvement in individual studies is often limited, their involvement in guiding health research is generally considered to be beneficial. This paper outlines our experiences of an integrated relationship between the organisers of a clinical trial and a consumer organisation. The PRISM trial is a UK multicentre, randomized controlled trial comparing treatment strategies for Paget's disease of the bone. The National Association for the Relief of Paget's Disease (NARPD) is the only UK support group for sufferers of Paget's disease and has worked closely with the PRISM team from the outset. NARPD involvement is integral to the conduct of the trial and specific roles have included: peer-review; trial steering committee membership; provision of advice to participants, and promotion of the trial amongst Paget's disease patients. The integrated relationship has yielded benefits to both the trial and the consumer organisation. The benefits for the trial have included: recruitment of participants via NARPD contacts; well-informed participants; unsolicited patient advocacy of the trial; and interested and pro-active collaborators. For the NARPD and Paget's disease sufferers, benefits have included: increased awareness of Paget's disease; increased access to relevant health research; increased awareness of the NARPD services; and wider transfer of diagnosis and management knowledge to/from health care professionals. Our experience has shown that an integrated approach between a trial team and a consumer organisation is worthwhile. Adoption of such an approach in other trials may yield significant improvements in recruitment and quality of participant information flow. There are, however, resource implications for both parties.

A centralised public information resource for randomised trials: a scoping study to explore desirability and feasibility.

BACKGROUND: There are currently several concerns about the ways in which people are recruited to participate in randomised controlled trials, the low acceptance rates among people invited to participate, and the experiences of trial participants. An information resource about on-going clinical trials designed for potential and current participants could help overcome some of these problems. METHODS: We carried out a scoping exercise to explore the desirability and feasibility of establishing such a resource. We sought the views of a range of people including people who were considering taking part in a trial, current trial participants, people who had been asked but refused to participate in a trial, consumer group representatives and researchers who design and conduct trials. RESULTS: There was broad-based support for the concept of a centralised information resource for members of the public about on-going and recently completed clinical trials. Such an information resource could be based on a database containing standardised information for each trial relating to the purpose of the trial; the interventions being compared; the implications of participation for participants; and features indicative of scientific quality and ethical probity. The usefulness of the database could be enhanced if its search facility could allow people to enter criteria such as a disease and geographic area and be presented with all the trials relevant to them, and if optional display formats could allow them to view information in varying levels of detail. Access via the Internet was considered desirable, with complementary supported access via health information services. The development of such a resource is technically feasible, but the collation of the required information would take a significant investment of resources. CONCLUSION: A centralised participant oriented information resource about clinical trials could serve several purposes. A more detailed investigation of its feasibility and exploration of its potential impacts are required.