David Purves
Robertson Centre for Biostatistics
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Featured researches published by David Purves.
BMJ | 2015
David Tappin; Linda Bauld; David Purves; Kathleen A Boyd; Lesley Sinclair; Susan MacAskill; Jennifer McKell; Brenda Friel; Alex McConnachie; Linda de Caestecker; Carol Tannahill; Andrew Radley; Tim Coleman
Objective To assess the efficacy of a financial incentive added to routine specialist pregnancy stop smoking services versus routine care to help pregnant smokers quit. Design Phase II therapeutic exploratory single centre, individually randomised controlled parallel group superiority trial. Setting One large health board area with a materially deprived, inner city population in the west of Scotland, United Kingdom. Participants 612 self reported pregnant smokers in NHS Greater Glasgow and Clyde who were English speaking, at least 16 years of age, less than 24 weeks pregnant, and had an exhaled carbon monoxide breath test result of 7 ppm or more. 306 women were randomised to incentives and 306 to control. Interventions The control group received routine care, which was the offer of a face to face appointment to discuss smoking and cessation and, for those who attended and set a quit date, the offer of free nicotine replacement therapy for 10 weeks provided by pharmacy services, and four, weekly support phone calls. The intervention group received routine care plus the offer of up to £400 of shopping vouchers: £50 for attending a face to face appointment and setting a quit date; then another £50 if at four weeks’ post-quit date exhaled carbon monoxide confirmed quitting; a further £100 was provided for continued validated abstinence of exhaled carbon monoxide after 12 weeks; a final £200 voucher was provided for validated abstinence of exhaled carbon monoxide at 34-38 weeks’ gestation. Main outcome measure The primary outcome was cotinine verified cessation at 34-38 weeks’ gestation through saliva (<14.2 ng/mL) or urine (<44.7 ng/mL). Secondary outcomes included birth weight, engagement, and self reported quit at four weeks. Results Recruitment was extended from 12 to 15 months to achieve the target sample size. Follow-up continued until September 2013. Of the 306 women randomised, three controls opted out soon after enrolment; these women did not want their data to be used, leaving 306 intervention and 303 control group participants in the intention to treat analysis. No harms of financial incentives were documented. Significantly more smokers in the incentives group than control group stopped smoking: 69 (22.5%) versus 26 (8.6%). The relative risk of not smoking at the end of pregnancy was 2.63 (95% confidence interval 1.73 to 4.01) P<0.001. The absolute risk difference was 14.0% (95% confidence interval 8.2% to 19.7%). The number needed to treat (where financial incentives need to be offered to achieve one extra quitter in late pregnancy) was 7.2 (95% confidence interval 5.1 to 12.2). The mean birth weight was 3140 g (SD 600 g) in the incentives group and 3120 (SD 590) g in the control group (P=0.67). Conclusion This phase II randomised controlled trial provides substantial evidence for the efficacy of incentives for smoking cessation in pregnancy; as this was only a single centre trial, incentives should now be tested in different types of pregnancy cessation services and in different parts of the United Kingdom. Trial registration Current Controlled Trials ISRCTN87508788.
Annals of the Rheumatic Diseases | 2016
James Dale; Anne Stirling; Ruiqi Zhang; David Purves; Jonathan Foley; Martin Sambrook; Philip G. Conaghan; Désirée van der Heijde; Alex McConnachie; Iain B. McInnes; Duncan Porter
Objective To investigate whether an intensive early rheumatoid arthritis (RA) treat-to-target (T2T) strategy could be improved through the use of musculoskeletal ultrasound (MSUS) assessment of disease activity. Methods 111 newly diagnosed patients with RA or undifferentiated arthritis (symptom duration <1 year) were randomised to strategies that aimed to attain either DAS28-erythrocyte sedimentation rate (ESR)<3.2 (control) or a total power Doppler joint count≤1 during a combined DAS28-ESR/MSUS assessment (intervention). MSUS examination was indicated if: DAS28-ESR<3.2 or DAS28-ESR≥3.2 with two swollen joints. Step-up disease-modifying antirheumatic drug (DMARD) escalation was standardised: methotrexate monotherapy, triple therapy and then etanercept/triple therapy. American College of Rheumatology (ACR) core-set variables were assessed 3 monthly by a metrologist blinded to group allocation. MRI of dominant hand and wrist, and plain radiographs of hands and feet were undertaken at baseline and 18 months for grading by two readers using the Outcome Measures in Rheumatology (OMERACT) Rheumatoid Arthritis MRI Scoring System (RAMRIS) and van der Heijde/Sharp Score, respectively. The coprimary outcomes were mean change from baseline of DAS44 and RAMRIS erosion score. Results Groups were matched for baseline clinical, demographic and radiographic features. The intervention group received more intensive DMARD therapy. Both groups demonstrated significant improvements in DAS44 (mean change: control −2.58, intervention −2.69; 95% CI difference between groups −0.70 to 0.48; p=0.72). There were no significant between-group differences for any ACR core-set variables, except DAS44 remission after 18 months (control 43%, intervention 66%; p=0.03). There was minimal progression of MRI and radiographic erosions and no difference in imaging outcomes or serious adverse event rates. Conclusions In early RA, a MSUS-driven T2T strategy led to more intensive treatment, but was not associated with significantly better clinical or imaging outcomes than a DAS28-driven strategy. Trial registration number NCT00920478.
Arthritis Care and Research | 2014
James Dale; David Purves; Alex McConnachie; Iain B. McInnes; Duncan Porter
To determine the level of agreement and potential impact on disease‐modifying antirheumatic drug (DMARD) escalation decisions and of adding musculoskeletal ultrasound (MSUS) assessment of disease activity to the Disease Activity Score in 28 joints (DAS28) in early rheumatoid arthritis (RA).
PLOS ONE | 2013
Bhautesh Dinesh Jani; David Purves; Sarah Barry; Jonathan Cavanagh; Gary McLean; Frances Mair
Background Depression screening in chronic disease is advocated but its impact on routine practice is uncertain. We examine the effects of a programme of incentivised depression screening in chronic disease within a UK primary care setting. Methods and Findings Cross sectional analysis of anonymised, routinely collected data (2008-9) from family practices in Scotland serving a population of circa 1.8 million. Primary care registered patients with at least one of three chronic diseases, coronary heart disease, diabetes and stroke, underwent incentivised depression screening using the Hospital Anxiety and Depression Score (HADS). 125143 patients were identified with at least one chronic disease. 10670 (8.5%) were under treatment for depression and exempt from screening. Of remaining, HADS were recorded for 35537 (31.1%) patients. 7080 (19.9% of screened) had raised HADS (≥8); majority had indications of mild depression with HADS between 8 and 10. Over 6 months, 572 (8%) of those with raised HADS (≥8) were initiated on antidepressants, while 696 (2.4%) patients with normal HADS (<8) were also initiated on antidepressants (relative risk of antidepressant initiation with raised HADS 3.3 (CI 2.97-3.67), p value <0.0001). Of those with multimorbidity who were screened, 24.3% had raised HADS (≥8). A raised HADS was more likely in females, socioeconomically deprived, multimorbid or younger (18-44) individuals. Females and 45-64 years old were more likely to receive antidepressants. Limitations retrospective study of routinely collected data. Conclusions Despite incentivisation, only a minority of patients underwent depression screening, suggesting that systematic depression screening in chronic disease can be difficult to achieve in routine practice. Targeting those at greatest risk such as the multimorbid or using simpler screening methods may be more effective. Raised HADS was associated with higher number of new antidepressant prescriptions which has significant resource implications. The clinical benefits of such screening remain uncertain and merits investigation.
BMC Pediatrics | 2014
Christine Puckering; Clare Allely; Orla Doolin; David Purves; Alex McConnachie; Paul Johnson; Helen Marwick; Jon Heron; Jean Golding; Christopher Gillberg; Philip Wilson
BackgroundEffective early intervention to prevent oppositional/conduct disorders requires early identification of children at risk. Patterns of parent-child interaction may predict oppositional/conduct disorders but large community-based prospective studies are needed to evaluate this possibility.MethodsWe sought to examine whether the Mellow Parenting Observational System (MPOS) used to assess parent-infant interactions at one year was associated with psychopathology at age 7. The MPOS assesses positive and negative interactions between parent and child. It examines six dimensions: anticipation of child’s needs, responsiveness, autonomy, cooperation, containment of child distress, and control/conflict; these are summed to produce measures of total positive and negative interactions. We examined videos from the Avon Longitudinal Study of Parents and Children (ALSPAC) sub-cohort who attended the ‘Children in Focus’ clinic at one year of age. Our sample comprised 180 videos of parent-infant interaction: 60 from infants who received a psychiatric diagnostic categorisation at seven years and 120 randomly selected controls who were group-matched on sex.ResultsA negative association between positive interactions and oppositional/conduct disorders was found. With the exception of pervasive developmental disorders (autism), an increase of one positive interaction per minute predicted a 15% (95% CI: 4% to 26%) reduction in the odds of the infant being case diagnosed. There was no statistically significant relationship between negative parenting interactions and oppositional/conduct disorders, although negative interactions were rarely observed in this setting.ConclusionsThe Mellow Parenting Observation System, specifically low scores for positive parenting interactions (such as Responsiveness which encompasses parental warmth towards the infant), predicted later psychiatric diagnostic categorisation of oppositional/conduct disorders.
PLOS ONE | 2015
Nazim Ghouri; David Purves; Kevin A. Deans; Greig Logan; Alex McConnachie; John Wilson; Jason M. R. Gill; Naveed Sattar
Objectives Ultrasound studies of carotid intima media thickness (cIMT) and plaques are limited in South Asians, a group at elevated cardiovascular disease (CVD) risk. We determined whether South Asians have a difference in these ultrasound markers compared to Europeans living in the United Kingdom and whether measured risk factor(s) could account for any such differences. Methods One hundred South Asian men, aged 40 to 70 years and 100 European men of similar age and BMI, without diagnosed CVD or diabetes, underwent carotid ultrasound for measurement of cIMT and carotid plaque presence. Physical activity, cardiorespiratory fitness, anthropometry and blood pressure were assessed, fasted blood taken for measurement of cardiometabolic risk factors and demographic and lifestyle factors recorded. Results Age-adjusted mean (SD) cIMT was similar in South Asians and Europeans (0.64 (0.16) mm v 0.65 (0.12) mm, p = 0.64). Plaque was present in 48 South Asians and 37 Europeans and overall, there was no age-adjusted difference between South Asian and Europeans for plaque score(odds ratio 1.49, 95% CI, 0.86-2.80, p = 0.16), however, South Asians appeared to have more plaques at a younger age than Europeans; at age 40-50 years the odds of South Asians having plaques was 2.63 (95% CI, 1.16-5.93) times that for Europeans. Conclusions cIMT is similar between healthy South Asian and European men. Whilst there was no overall difference in plaque presence in South Asians, there is an indication of greater plaque prevalence at younger ages - an observation requiring further investigation. Prospective studies linking plaques to CVD outcomes in South Asians are needed to investigate whether these measures help improve CVD risk prediction.
Research in Developmental Disabilities | 2013
Clare Allely; David Purves; Alex McConnachie; Helen Marwick; Paul Johnson; Orla Doolin; Christine Puckering; Jean Golding; Christopher Gillberg; Philip Wilson
Highlights ► Reduced caregiver vocalisations were associated with development of disruptive behaviour disorders. ► Higher infant vocalisations were associated with disruptive behaviour disorders. ► Study into parental vocalisation behaviours early in life may be clinically important.
Research in Developmental Disabilities | 2016
Craig A. Melville; Paul Johnson; Elita Smiley; Neill Simpson; David Purves; Alex McConnachie; Sally-Ann Cooper
BACKGROUND The limited evidence on the relationship between problem behaviours and symptoms of psychiatric disorders experienced by adults with intellectual disabilities leads to conflict about diagnostic criteria and confused treatment. This study examined the relationship between problem behaviours and other psychopathology, and compared the predictive validity of dimensional and categorical models experienced by adults with intellectual disabilities. METHODS Exploratory and confirmatory factor analyses appropriate for non-continuous data were used to derive, and validate, symptom dimensions using two clinical datasets (n=457; n=274). Categorical diagnoses were derived using DC-LD. Severity and 5-year longitudinal outcome was measured using a battery of instruments. RESULTS Five factors/dimensions were identified and confirmed. Problem behaviours were included in an emotion dysregulation-problem behaviour dimension that was distinct from the depressive, anxiety, organic and psychosis dimensions. The dimensional model had better predictive validity than categorical diagnosis. CONCLUSIONS International classification systems should not include problem behaviours as behavioural equivalents in diagnostic criteria for depression or other psychiatric disorders. Investigating the relevance of emotional regulation to psychopathology may provide an important pathway for development of improved interventions. WHAT THIS PAPER ADDS There is uncertainty whether new onset problem behaviours or a change in longstanding problem behaviours should be considered as symptoms of depression or other types of psychiatric disorders in adults with intellectual disabilities. The validity of previous studies was limited by the use of pre-defined, categorical diagnoses or unreliable statistical methods. This study used robust statistical modelling to examine problem behaviours within a dimensional model of symptoms. We found that problem behaviours were included in an emotional dysregulation dimension and not in the dimension that included symptoms that are typical of depression. The dimensional model of symptoms had greater predictive validity than categorical diagnoses of psychiatric disorders. Our findings suggest that problem behaviours are a final common pathway for emotional distress in adults with intellectual disabilities so clinicians should not use a change in problem behaviours as a diagnostic criterion for depression, or other psychiatric disorders.
Research in Developmental Disabilities | 2016
Craig A. Melville; Paul Johnson; Elita Smiley; N. Simpson; Alex McConnachie; David Purves; M. Osugo; Sally-Ann Cooper
Diagnosing mental ill-health using categorical classification systems has limited validity for clinical practice and research. Dimensions of psychopathology have greater validity than categorical diagnoses in the general population, but dimensional models have not had a significant impact on our understanding of mental ill-health and problem behaviours experienced by adults with intellectual disabilities. This paper systematically reviews the methods and findings from intellectual disabilities studies that use statistical methods to identify dimensions of psychopathology from data collected using structured assessments of psychopathology. The PRISMA framework for systematic review was used to identify studies for inclusion. Study methods were compared to best-practice guidelines on the use of exploratory factor analysis. Data from the 20 studies included suggest that it is possible to use statistical methods to model dimensions of psychopathology experienced by adults with intellectual disabilities. However, none of the studies used methods recommended for the analysis of non-continuous psychopathology data and all 20 studies used statistical methods that produce unstable results that lack reliability. Statistical modelling is a promising methodology to improve our understanding of mental ill-health experienced by adults with intellectual disabilities but future studies should use robust statistical methods to build on the existing evidence base.
Obstetrical & Gynecological Survey | 2015
David Tappin; Linda Bauld; David Purves; Kathleen A Boyd; Lesley Sinclair; Susan MacAskill; Jenniffer McKell; Brenda Friel; Alex McConnachie; Linda de Caestecker; Carol Tannahill; Andrew Radley; Tim Coleman
Each year, 25,000 spontaneous miscarriages are associated with smoking during pregnancy. While there are many medical approaches to smoking cessation, they have not proven to be the particularly effective. A recent Cochrane systematic review suggests that financial incentives may be effective in helping pregnant smokers quit. The current study explored the efficacy and cost-effectiveness of financial incentives added to routine specialist pregnancy NHS “Stop Smoking Services” that provide assistance to pregnant women to quit smoking. The design of this study used a phase II therapeutic randomized controlled trial in a single center that covered a wide geographical location. Women eligible for the study were smokers who had a carbon monoxide measurement of 7 ppm, were 16 years or younger, at less than 24 weeks’ gestation, and resident in NHS Greater Glasgow and Clyde. All eligible women were allocated to a control group (306) or incentives (306). The routine specialist pregnancy care consisted of a face-to-face appointment followed by 4 weekly phone support calls and free nicotine replacement therapy for 10 weeks, with a confirmation of smoking status at 4 and 12 weeks of agreed quit date. Control groups were offered routine support; an intervention group received a £50 voucher for attending all appointments and to set a quit date. The incentive group was also offered £400 shopping vouchers if they engaged with stop smoking services or quit. Those who remained abstinent, confirmed by a carbon monoxide breath test (<10 ppm), in the intervention group were also given additional £50 vouchers at 2 weeks and £100 vouchers at 12 weeks. A final £200 voucher was given to the incentive group when confirmed smoking abstinence at quit date. In the primary outcome assessment, there was a significant difference between the 2 groups. More women had stopped smoking in the incentives group (22.5% vs 8.6 %; P < 0.001), and relative risk of not smoking at the end of pregnancy was 2.63 (95% confidence interval, 1.73–4.01). Secondary outcome assessment revealed a higher rate of continued abstinence 4 weeks after quit date in the incentives group. This study suggests that financial incentives can aid women to quit smoking during pregnancy and are more effective than other approaches currently recommended. The cost of this incentive is also below the current UK National Health Service threshold and is a cost-effective option in the short term. Smoking during pregnancy may prevent both maternal and neonatal complications, and financial incentives should be considered as a more effective method to avoid these conditions than the current incentives provided.