Causal association between subtypes of osteoarthritis and common comorbidities: A Mendelian randomisation study

Objective

To investigate the causal association between Osteoarthritis (OA) and five comorbidities: depression, tiredness, multisite chronic pain, irritable bowel syndrome (IBS) and gout.

Design

This study used two-sample Mendelian Randomisation (MR). To select the OA genetic instruments, we used data from the largest recent genome-wide association study (GWAS) of OA (GO Consortium), with a focus on OA of the knee (62,497 cases, 333,557 controls), hip (35,445 cases, 316,943 controls) and hand (20,901 cases, 282,881 controls). Genetic associations for comorbidities were selected from GWAS for depression (246,363 cases, 561,190 controls), tiredness (449,019 participants), multisite chronic pain (387,649 participants), IBS (53,400 cases, 433,201 controls) and gout (6543 cases, 456,390 controls). We performed a bidirectional MR analysis using the inverse variance weighted method, for both joint specific and overall OA.

Results

Hip OA had a causal effect on multisite chronic pain (per unit change 0.02, 95% CI 0.01 to 0.04). Multisite chronic pain had a causal effect on knee (odd ratio (OR) 2.74, 95% CI 2.20 to 3.41), hip (OR 2.12, 95% CI 1.54 to 2.92), hand (OR 2.24, 95% CI 1.59 to 3.16) and overall OA (OR 2.44, 95% CI, 2.06 to 2.86). In addition, depression and tiredness had causal effects on knee and hand, but not hip, OA.

Conclusions

Apart from Hip OA to multisite chronic pain, other joint OA did not have causal effects on these comorbidities. In contrast, multisite chronic pain had a causal effect on any painful OA.

Classification of patients with osteoarthritis through clusters of comorbidities using 633 330 individuals from Spain

OBJECTIVES

To explore clustering of comorbidities among patients with a new diagnosis of OA and estimate the 10-year mortality risk for each identified cluster.

METHODS

This is a population-based cohort study of individuals with first incident diagnosis of OA of the hip, knee, ankle/foot, wrist/hand or 'unspecified' site between 2006 and 2020, using SIDIAP (a primary care database representative of Catalonia, Spain). At the time of OA diagnosis, conditions associated with OA in the literature that were found in ≥1% of the individuals (n = 35) were fitted into two cluster algorithms, k-means and latent class analysis. Models were assessed using a range of internal and external evaluation procedures. Mortality risk of the obtained clusters was assessed by survival analysis using Cox proportional hazards.

RESULTS

We identified 633 330 patients with a diagnosis of OA. Our proposed best solution used latent class analysis to identify four clusters: 'low-morbidity' (relatively low number of comorbidities), 'back/neck pain plus mental health', 'metabolic syndrome' and 'multimorbidity' (higher prevalence of all studied comorbidities). Compared with the 'low-morbidity' cluster, the 'multimorbidity' cluster had the highest risk of 10-year mortality (adjusted hazard ratio [HR]: 2.19 [95% CI: 2.15, 2.23]), followed by the 'metabolic syndrome' cluster (adjusted HR: 1.24 [95% CI: 1.22, 1.27]) and the 'back/neck pain plus mental health' cluster (adjusted HR: 1.12 [95% CI: 1.09, 1.15]).

CONCLUSION

Patients with a new diagnosis of OA can be clustered into groups based on their comorbidity profile, with significant differences in 10-year mortality risk. Further research is required to understand the interplay between OA and particular comorbidity groups, and the clinical significance of such results.

Comorbidity in incident osteoarthritis cases and matched controls using electronic health record data

BACKGROUND

Comorbidities are common in patients with osteoarthritis (OA). This study aimed to determine the association of a wide range of previously diagnosed comorbidities in adults with newly diagnosed OA compared with matched controls without OA.

METHODS

A case-control study was conducted. The data were derived from an electronic health record database that contains the medical records of patients from general practices throughout the Netherlands. Incident OA cases were defined as patients with one or more diagnostic codes recorded in their medical records that correspond to knee, hip, or other/peripheral OA. Additionally, the first OA code had to be recorded between January 1, 2006, and December 31, 2019. The date of cases' first OA diagnosis was defined as the index date. Cases were matched (by age, sex, and general practice) to up to 4 controls without a recorded OA diagnosis. Odds ratios were derived for each 58 comorbidities separately by dividing the comorbidity prevalence of cases by that of their matched controls at the index date.

RESULTS

80,099 incident OA patients were identified of whom 79,937 (99.8%) were successfully matched with 318,206 controls. OA cases had higher odds for 42 of the 58 studied comorbidities compared with matched controls. Musculoskeletal diseases and obesity showed large associations with incident OA.

CONCLUSIONS

Most of the comorbidities under study had higher odds in patients with incident OA at the index date. While previously known associations were confirmed in this study, some associations were not described earlier.

Occurrence of comorbidity following osteoarthritis diagnosis: a cohort study in the Netherlands

OBJECTIVE

To determine the risk of comorbidity following diagnosis of knee or hip osteoarthritis (OA).

DESIGN

A cohort study was conducted using the Integrated Primary Care Information database, containing electronic health records of 2.5 million patients from the Netherlands. Adults at risk for OA were included. Diagnosis of knee or hip OA (=exposure) and 58 long-term comorbidities (=outcome) were defined by diagnostic codes following the International Classification of Primary Care coding system. Time between the start of follow-up and incident diagnosis of OA was defined as unexposed, and between diagnosis of OA and the end of follow-up as exposed. Age and sex adjusted hazard ratios (HRs) comparing comorbidity rates in exposed and unexposed patient time were estimated with 99.9% confidence intervals (CI).

RESULTS

The study population consisted of 1,890,712 patients. For 30 of the 58 studied comorbidities, exposure to knee OA showed a HR larger than 1. Largest positive associations (HR with (99.9% CIs)) were found for obesity 2.55 (2.29-2.84) and fibromyalgia 2.06 (1.53-2.77). For two conditions a HR < 1 was found, other comorbidities showed no association with exposure to knee OA. For 26 comorbidities, exposure to hip OA showed a HR larger than 1. The largest were found for polymyalgia rheumatica 1.81 (1.41-2.32) and fibromyalgia 1.70 (1.10-2.63). All other comorbidities showed no associations with hip OA.

CONCLUSION

This study showed that many comorbidities were diagnosed more often in patients with knee or hip OA. This suggests that the management of OA should consider the risk of other long-term-conditions.

Medical students' perception of general practice: a cross-sectional survey

BACKGROUND

An increase in the demand for general practitioners is expected in many countries, but only a minority of medical students consider a career in general practice. More detailed and up-to-date knowledge about medical student's perception of general practice would be helpful for efforts to encourage medical students to consider a career in general practice.

METHODS

We performed a cross-sectional single center survey among Dutch medical students to evaluate their perception of general practice at three different stages in their study: Ba1: first-year bachelor students; Ba3: third-year bachelor students; Ma3: third-year master students. The impact of different factors on their attitudes and perceptions was quantified. A multivariate logistic regression was performed with 'interest in general practice' as the outcome variable.

RESULTS

The median age for Ba1 was 18 (IQR: 18-19) and 71.5% were female, for Ba3 the median age was 20 (IQR: 20-21) and 70.6% were female and for Ma3 the median age was 25 years (IQR: 24-26) and 73.3% were female. On average, 31.2% of the respondents had a migration background. The mean response rate for this study was 77.1%. Of the participating Ba1 students (n = 340) only 22.4% considered working as a GP after medical school; for Ba3 students (n = 231) this percentage was 33.8%, and for Ma3 students (n = 210) it was significantly higher at 70.5%; in the final multivariate model this corresponded to an odds ratio (OR) of 4.3 (95%-CI:2.6-6.9) compared to Ba1 students. The strongest predictor in the final model was the opinion that general practice provides a pleasant working environment (OR 9.5; 95%-CI: 6.2-14.5).

CONCLUSION

This study showed that multiple factors are significantly related to medical students' interest in general practice. Although students believed that general practice does not have a high status within the medical profession, they acknowledged the social importance and the pleasant working environment of general practice. Knowledge obtained in this study can be used when designing a medical curriculum or a general practice course.

OP0228 USE OF NON-STEROIDAL ANTI-INFLAMMATORY DRUGS AND RISK OF COMORBIDITIES IN PEOPLE WITH AND WITHOUT OSTEOARTHRITIS - A UK PRIMARY CARE DATABASE COHORT STUDY

Background

People with osteoarthritis (OA) are at higher risk of developing a wide array of comorbidities. Whether the use of non-steroidal anti-inflammatory drugs (NSAIDs) contributes to the increased risk of some incident comorbidities remains unknown.

Objectives

To examine the contribution of NSAIDs in the development of a wide range of comorbidities in people with and without OA.

Methods

This observational cohort study used the UK primary care Clinical Practice Research Datalink (CPRD) GOLD containing data on 20+ million people covering 937 practices. We identified 259,000 people with incident OA and 259,000 age (±2 years), sex, and practice matched controls at 1:1 ratio. Controls were assigned the same index date (the date of first diagnosis of OA) as cases for the start of follow-up. Both cases and controls were further divided into two groups according to NSAID prescriptions at any time after the index date. This allowed us to examine both the main effect of each exposure and interaction between OA and NSAID exposure after the index date. People with an NSAID prescription before the index date were excluded from the study. NSAID exposure was defined as at least two prescriptions within 90 days. Exposure status of each participant was assessed every six months as yes/no until the end of the study/outcome of interests/death/last data available, whichever came first. Comorbidities were grouped into 9 categories as cancer, cardiovascular disease (CVD), endocrine, psychological, renal, gastrointestinal (GI), genitourinary, hepatic, and neurological conditions. Propensity scores for the prescription of NSAIDs were calculated using a logistic regression model including age, sex, body mass index (BMI), musculoskeletal and pain related conditions covariates. The propensity score adjusted time varying exposure analysis was undertaken using a multivariate COX model and hazard ratio (HR) and 95% confidence intervals were calculated. Proportional hazard assumption was tested using Schoenfeld test. Smoking, alcohol, ever prescription of proton pump inhibitors (PPIs) and other comorbidities were included in the adjusted model. The additional contribution of NSAIDs and OA towards the incident comorbidity was estimated using addictive interaction methods. We also investigated the individual risk across non-selective, and COX-2 selective NSAIDs.

Results

The mean age was 59.4±12.8 years in people with OA and 60.2±12.8 years for controls with 57.7% being female. Nearly two thirds of people with OA were prescribed NSAIDs as defined, compared to one third in the control population. People with OA and exposed to NSAIDs had highest risk of developing psychological (1.51; 1.43,1.60), CVD (1.38; 1.33,1.43), cancer (1.34; 1.25,1.44), GI (1.25; 1.16,1.34) and renal (1.17; 1.11,1.24) comorbidities after adjusting for all the covariates and PPI drugs, compared to the non-OA and non-NSAID group. (Figure 1) Interaction between OA and NSAID was significant for cancer, GI, renal, hepatic, and neurological outcomes. Within people with OA, non-selective NSAIDs increased the risk of CVD (1.25; 1.20,1.30), cancer (1.11; 1.04,1.19), endocrine (1.15; 1.10,1.19), renal (1.19; 1.13,1.26) and psychological (1.21; 1.15,1.28) comorbidities, whereas COX-2 selective NSAIDs increased risk of incident CVD (1.34; 1.25,1.44), endocrine (1.13; 1.04,1.21), renal (1.25; 1.14,1.37), and psychological (1.21; 1.09,1.34) comorbidities.

Figure 1.

Hazard ratio of developing different comorbidities (reference group: no OA and no NSAIDs) OA- Osteoarthritis; NSAIDS- Non-steroidal anti-inflammatory drugs.

Conclusion

Use of NSAIDs among people with OA is associated with increased risk of a wide variety of comorbidities. Non-selective and COX-2 selective NSAIDs are both associated with increased risk of cardiovascular, renal, and psychological comorbidities.

Acknowledgements

We thank the Patient Research Participants (PRP) members Jenny Cockshull, Stevie Vanhegan, and Irene Pitsillidou for their involvement since the beginning of the project. We would like to thank the FOREUM for financially supporting the research.

Disclosure of Interests

Subhashisa Swain: None declared, Anne Kamps: None declared, Jos Runhaar: None declared, Andrea Dell’Isola: None declared, Aleksandra Turkiewicz: None declared, Danielle E Robinson: None declared, Victoria Y Strauss: None declared, Christian Mallen: None declared, Chang-Fu Kuo: None declared, Carol Coupland: None declared, Michael Doherty Consultant of: Consultant of: Advisory borads on gout for Grunenthal and Mallinckrodt, Grant/research support from: Michael Doherty Grant/research support from: AstraZeneca funded the Nottingham Sons of Gout study, Aliya Sarmanova: None declared, Daniel Prieto-Alhambra Speakers bureau: paid speaker services from Amgen and UCB Biopharma., Consultant of: His department has received advisory or consultancy fees from Amgen, Astellas, AstraZeneca, Johnson, and Johnson, and UCB Biopharma, Grant/research support from: Prof. Prieto-Alhambra’s research group has received grant support from Amgen, Chesi-Taylor, Novartis, and UCB Biopharma., Martin Englund: None declared, S.M.A. Bierma-Zeinstra: None declared, Weiya Zhang Speakers bureau: Speakers bureau: Bioiberica as an invited speaker for EULAR 2016 satellite symposium, Consultant of: Consultant of: Grunenthal for advice on gout management,

POS1124 EVALUATION OF COMORBIDITY PATTERNS AND IDENTIFICATION OF SUB-GROUPS IN PATIENTS DIAGNOSED WITH HIP OSTEOARTHRITIS IN 94,720 PATIENTS FROM SPAIN

Background

Osteoarthritis (OA) patients are more likely to have other comorbidities (Swain, Sarmanova et al. 2020). Improving the understanding of comorbidity profiles of OA patients may lead to improvement in their clinical care.

Objectives

To identify sub-groups in patients diagnosed with hip OA using patterns of comorbidity.

Methods

Routinely-collected data of individuals ≥18 years with an incident diagnosis of hip OA (baseline/time of diagnosis), with at least 1 year of follow-up in SIDIAP (Information System for Research in Primary Care, a primary case database from Spain) were collected from January 1st 2006 to June 31st 2020. Those with soft-tissue disorders or other bone/cartilage diseases at the same joint in the year prior/after baseline were excluded. Comorbidities associated with OA in the literature and present in ≥1% of the study population were included. Clusters of comorbidities were identified at baseline using latent class analysis (LCA), a soft clustering method that classifies individuals according to the distribution of their measured items. The number of clusters or sub-groups within the study population was decided by comparing goodness of fit parameters (CAIC, BIC, ABIC) and log-likelihood changes of models from 2 to 8 clusters. The selected model was externally evaluated by a survival analysis assessing 10 years mortality within each cluster, where the weight of the posterior probability was used as a probability of sampling weight.

Results

We identified 94,720 individuals with an incident diagnosis of hip OA, 56.3% women and 43.7% men, with a mean age (SD) of 67.2 (13.1) years. We selected the LCA model with 5 clusters that could be described as: healthier (lower prevalence of all comorbidities than average in the cohort), multimorbidity (higher prevalence of all comorbidities, multiple comorbidities), back/neck pain plus mental health (B/N-mental), cardiovascular disease (CVD), and metabolic syndrome (MetS) (Figure 1). Cox regression (HR [95CI%]) showed higher mortality risk for multimorbidity (3.76 [3.70-3.83]), CVD (1.56 [1.53-1.59]) and MetS (4.56 [4.35-4.78]), compared to healthy. No difference was observed for B/N-mental cluster.

Figure 1.

Distribution of comorbidities within each cluster using latent class analysis. Clusters were described as Healthier, Multimorbidity, B/N-mental, CVD and MetS. Black horizontal lines represent the prevalence of the comorbidity before the clusterization. Abbreviations: Healthier, lower prevalence of all comorbidities; Multimorbidity, higher prevalence of all comorbidities; B/N-mental, back/neck pain plus mental health disorders; CVD, cardiovascular disease; Met, metabolic syndrome; Bhp, benign prostate hypertrophy; Chd, chronic heart disease; Chf, chronic heart failure; Ckd, chronic kidney disease; Copd, chronic obstructive pulmonary disease; Gbs, gall bladder stone; Gerd, gastroesophageal reflux disease; Ibd, inflammatory bowel disease; Ovd, other vessel diseases; Substance, substance abuse.

Conclusion

Clustering of co-morbidities in hip OA patients at the time of diagnosis has the potential to detect sub-groups of hip OA patients who might require additional care.

References

[1]Swain, S., A. Sarmanova, C. Coupland, M. Doherty and W. Zhang (2020). “Comorbidities in Osteoarthritis: A Systematic Review and Meta-Analysis of Observational Studies.” Arthritis Care Res (Hoboken) 72(7): 991-1000.

Acknowledgements

We thank the Patient Research Participants (PRP) members Jenny Cockshull, Stevie Vanhegan, and Irene Pitsillidou for their involvement since the beginning of the project. We would like to thank the FOREUM for financially supporting the research.

Disclosure of Interests

None declared

OP0225 RISK OF COMORBIDITY FOLLOWING OSTEOARTHRITIS DIAGNOSIS: A COHORT STUDY IN THE NETHERLANDS FROM THE FOREUM* INITIATIVE

Background

Osteoarthritis (OA) is a common and disabling disease that places a significant burden on both patients and health care systems. Previous studies have already shown that patients with OA have a higher risk of developing comorbidities. However, many focused on one or a few conditions only, or did not consider the chronology of the disease onset relative to OA.

Objectives

To determine the risk of physician-diagnosed comorbidity following the diagnosis of knee or hip OA, using electronic health records in the Netherlands.

Methods

A cohort study was conducted using the Integrated Primary Care Information (IPCI) database, an electronic health record database with medical records of 2.5 million patients from Dutch general practice. The study population consisted of patients aged 18 years or older, that were at risk for incident OA and comorbidity. Diagnosis of knee or hip OA (i.e. exposure) was defined as the first registration of the corresponding diagnostic code from the International Classification of Primary Care (ICPC) coding system in the medical record. Fifty-eight long-term comorbidities (i.e. outcome) were selected and defined by their corresponding ICPC codes.

Patients’ follow-up started after registration in the database, and ended at the diagnosis date of the comorbidity (i.e. event), or at deregistration, death or at December 31st, 2019 (i.e. censoring), whichever came first. Exposure to knee or hip OA was a time-varying exposure: time between the start of follow-up and diagnosis of OA was defined as unexposed time, and between diagnosis of OA and the end of follow-up as exposed time. Patients’ age was used as time axis to correct for age non-linearly. Sex-adjusted hazard ratios (HRs) comparing exposed and unexposed patient status were estimated with 99.9% confidence intervals (CI).

Results

The study population consisted of 1,890,712 patients. For 11 of the 58 studied comorbidities exposure to knee OA showed a statistically significant HR larger than 1, indicating an increased risk of being diagnosed with these comorbidities after a diagnosis of knee OA. For none of the comorbidities there was a statistically significant negative association (HR<1) with exposure to knee OA. For 7 comorbidities exposure to hip OA showed a statistically significant HR larger than 1. Again, for all other comorbidities the HR of hip OA was non-significant. For an overview of the statistically significant positive associations see Table 1.

Table 1.

Comorbidities with significant HRs of exposure to knee or hip OA

Knee OAHip OAComorbidityHR99.9% CIComorbidityHR99.9% CIAnemia1.331.091.64Anemia1.291.021.63Back pain1.281.041.57Atrial fibrillation1.461.141.88Cataract1.271.021.59Fibromyalgia6.091.2529.53Chronic kidney disease1.301.061.59Peripheral vascular disease1.641.092.49Coronary heart disease1.341.031.75Sleeping disorder1.441.101.87Gout1.431.012.03Solid malignancy1.321.111.55Hearing loss1.341.001.79Spinal disc herniation2.031.462.83Neck pain1.581.162.16Obesity2.021.063.83Sleeping disorder1.331.041.69Thromboembolic disease1.401.011.94

Conclusion

This study showed that certain comorbidities were diagnosed more often in patients exposed to knee or hip OA, and none were less frequently diagnosed in patients exposed OA. This suggests that the management of OA should consider the risk of other long-term-conditions and that further research on causality between OA and comorbidity is needed.

References

[1]*https://www.foreum.org/projects.cfm?projectid=159

Acknowledgements

We thank the Patient Research Participants members Jenny Cockshull, Stevie Vanhegan, and Irene Pitsillidou for their involvement in the project. We would like to thank the FOREUM for financially supporting the research.

Disclosure of Interests

None declared

Comorbidities in osteoarthritis (ComOA): a combined cross-sectional, case-control and cohort study using large electronic health records in four European countries

INTRODUCTION

Osteoarthritis (OA) is one of the leading chronic conditions in the older population. People with OA are more likely to have one or more other chronic conditions than those without. However, the temporal associations, clusters of the comorbidities, role of analgesics and the causality and variation between populations are yet to be investigated. This paper describes the protocol of a multinational study in four European countries (UK, Netherlands, Sweden and Spain) exploring comorbidities in people with OA.

METHODS AND ANALYSIS

This multinational study will investigate (1) the temporal associations of 61 identified comorbidities with OA, (2) the clusters and trajectories of comorbidities in people with OA, (3) the role of analgesics on incidence of comorbidities in people with OA, (4) the potential biomarkers and causality between OA and the comorbidities, and (5) variations between countries.A combined case-control and cohort study will be conducted to find the temporal association of OA with the comorbidities using the national or regional health databases. Latent class analysis will be performed to identify the clusters at baseline and joint latent class analysis will be used to examine trajectories during the follow-up. A cohort study will be undertaken to evaluate the role of non-steroidal anti-inflammatory drugs (NSAIDs), opioids and paracetamol on the incidence of comorbidities. Mendelian randomisation will be performed to investigate the potential biomarkers for causality between OA and the comorbidities using the UK Biobank and the Rotterdam Study databases. Finally, a meta-analyses will be used to examine the variations and pool the results from different countries.

ETHICS AND DISSEMINATION

Research ethics was obtained according to each database requirement. Results will be disseminated through the FOREUM website, scientific meetings, publications and in partnership with patient organisations.

Patient-reported burden of intensified surveillance and surgery in high-risk individuals under pancreatic cancer surveillance

In high-risk individuals participating in a pancreatic cancer surveillance program, worrisome features warrant for intensified surveillance or, occasionally, surgery. Our objectives were to determine the patient-reported burden of intensified surveillance and/or surgery, and to assess post-operative quality of life and opinion of surgery. Participants in our pancreatic cancer surveillance program completed questionnaires including the Cancer Worry Scale (CWS) and the Hospital Anxiety and Depression Scale (HADS). For individuals who underwent intensified surveillance, questionnaires before, during, and ≥ 3 weeks after were analyzed. In addition, subjects who underwent intensified surveillance in the past 3 years or underwent surgery at any time, were invited for an interview, that included the Short-Form 12 (SF-12). A total of 31 high-risk individuals were studied. During the intensified surveillance period, median CWS scores were higher (14, IQR 7), as compared to before (12, IQR 9, P = 0.007) and after (11, IQR 7, P = 0.014), but eventually returned back to baseline (P = 0.823). Median HADS scores were low: 5 (IQR 6) for anxiety and 3 (IQR 5) for depression, and they were unaffected by the intensified surveillance period. Of the 10 operated patients, 1 (10%) developed diabetes and 7 (70%) pancreatic exocrine insufficiency. The interviews yielded median quality-of-life scores comparable to the general population. Also, after surgery, patients’ attitudes towards surveillance were unchanged (5/10, 50%) or became more positive (4/10, 40%). Although patients were aware of the (sometimes benign) pathological outcome, when asked if surgery had been justified, only 20% (2/10) disagreed, and all would again have chosen to undergo surgery. In conclusion, in individuals at high risk for pancreatic cancer, intensified surveillance temporarily increased cancer worries, without affecting general anxiety or depression. Although pancreatic surgery led to substantial co-morbidity, quality of life was similar to the general population, and surgery did not negatively affect the attitude towards surveillance.

Step-down versus outpatient psychotherapeutic treatment for personality disorders: 6-year follow-up of the Ullevål personality project

BACKGROUND

Although psychotherapy is considered the treatment of choice for patients with personality disorders (PDs), there is no consensus about the optimal level of care for this group of patients. This study reports the results from the 6-year follow-up of the Ullevål Personality Project (UPP), a randomized clinical trial comparing outpatient individual psychotherapy with a long-term step-down treatment program that included a short-term day hospital treatment followed by combined group and individual psychotherapy.

METHODS

The UPP included 113 patients with PDs. Outcome was evaluated after 8 months, 18 months, 3 years and 6 years and was based on a wide range of clinical measures, such as psychosocial functioning, interpersonal problems, symptom severity, and axis I and II diagnoses.

RESULTS

At the 6-year follow-up, there were no statistically significant differences in outcome between the treatment groups. Effect sizes ranged from medium to large for all outcome variables in both treatment arms. However, patients in the outpatient group had a marked decline in psychosocial functioning during the period between the 3- and 6-year follow-ups; while psychosocial functioning continued to improve in the step-down group during the same period. This difference between groups was statistically significant.

CONCLUSIONS

The findings suggest that both hospital-based long-term step-down treatment and long-term outpatient individual psychotherapy may improve symptoms and psychosocial functioning in poorly functioning PD patients. Social and interpersonal functioning continued to improve in the step-down group during the post-treatment phase, indicating that longer-term changes were stimulated during treatment.

TRIAL REGISTRATION

NCT00378248.

The nitrate reductase and nitrite reductase operons and the narT gene of Staphylococcus carnosus are positively controlled by the novel two-component system NreBC

In Staphylococcus carnosus, the nreABC (for nitrogen regulation) genes were identified and shown to link the nitrate reductase operon (narGHJI) and the putative nitrate transporter gene narT. An nreABC deletion mutant, m1, was dramatically affected in nitrate and nitrite reduction and growth. Transcription of narT, narGHJI, and the nitrite reductase (nir) operon was severely reduced even when cells were cultivated anaerobically without nitrate or nitrite. nreABC transcripts were detected when cells were grown aerobically or anaerobically with or without nitrate or nitrite. NreA is a GAF domain-containing protein of unknown function. In vivo and in vitro studies showed that NreC is phosphorylated by NreB and that phospho-NreC specifically binds to a GC-rich palindromic sequence to enhance transcription initiation. This binding motif was found at the narGHJI, nir, and narT promoters but not at the moeB promoter. NreB is a cytosolic protein with four N-terminal cysteine residues. The second cysteine residue was shown to be important for NreB function. In vitro autophosphorylation of NreB was not affected by nitrate, nitrite, or molybdate. The nir promoter activity was iron dependent. The data provide evidence for a global regulatory system important for aerobic and anaerobic metabolism, with NreB and NreC forming a classical two-component system and NreB acting as a sensor protein with oxygen as the effector molecule.

The Ch14.18-GM-CSF fusion protein is effective at mediating antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in vitro

Granulocyte/macrophage-colony stimulating factor (GM-CSF) is very effective at enhancing antibody-dependent cellular cytotoxicity (ADCC) mediated by granulocytes and monocytes. Recently, a fusion protein consisting of GM-CSF and chimeric human/mouse anti-ganglioside G(D2) antibody Ch14.18 (Ch14.18-GM-CSF) has been generated to improve the effectiveness of immunotherapy by directing GM-CSF to the tumor microenvironment and prolonging its relatively short half-life. In this study, we examined the ability of this fusion protein to enhance the in vitro killing of G(D2)-expressing human neuroblastoma cells by granulocytes and mononuclear cells, as well as by complement. The Ch14.18-GM-CSF fusion protein was equally effective as the combination of equivalent amounts of free Ch14.18 and GM-CSF in mediating the killing of NMB7 neuroblastoma cells by granulocytes from seven of eight neuroblastoma patients. The fusion protein was also equally effective as the combination of Ch14.18 and GM-CSF in mediating ADCC by neuroblastoma patients' mononuclear cells. In addition, the fusion protein was as effective as Ch14.18 alone in directing complement-dependent cytotoxicity against NMB7 cells. Our results demonstrate that the biological activities expressed by ADCC and complement-dependent cytotoxicity of both monoclonal antibody Ch14.18 and GM-CSF are retained by the Ch14.18-GM-CSF fusion protein and lend further support for future clinical trials of this fusion protein in patients with neuroblastoma.

Morphometric analysis of the corneal endothelium with three different specular microscopes

The morphometry of the central corneal endothelium of 10 eyes in 10 subjects was analyzed with three different specular microscopes. Computer-assisted analysis was performed with only two microscopes (Zeiss and Keeler Konan sp 3300) because the third microscope (Topcon sp 1000) could not be adapted to our computerized system. With this Topcon microscope a grid with standard densities was used to compare the images with, in addition, we also performed manual cell counting on the same Topcon images. The coefficient of variation of the cell analysis of three different images per cornea with the four methods varied between 3.4 and 4.7 percent. One-way analysis of variance showed a significant difference between the Zeiss and the other microscopes. So only the Keeler Konan and the Topcon microscopes could be used interchangeably. The computerized image analysis permitted also an evaluation of the hexagonality. The results of polygonality were not significantly different between the Zeiss and the Keeler Konan. For clinical purposes the Topcon specular microscope is more advantageous than the other two methods, since it is the most rapid way to record and analyze specular images. But for more precise measurements an image processing system is indispensable.