Characterization of synovial fluid metabolomic phenotypes of cartilage morphological changes associated with osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is a multifactorial disease with etiological heterogeneity. The objective of this study was to classify OA subgroups by generating metabolomic phenotypes from human synovial fluid.

DESIGN

Post mortem synovial fluids (n = 75) were analyzed by high performance-liquid chromatography mass spectrometry (LC-MS) to measure changes in the global metabolome. Comparisons of healthy (grade 0), early OA (grades I-II), and late OA (grades III-IV) donor populations were considered to reveal phenotypes throughout disease progression.

RESULTS

Global metabolomic profiles in synovial fluid were distinct between healthy, early OA, and late OA donors. Pathways differentially activated among these groups included structural deterioration, glycerophospholipid metabolism, inflammation, central energy metabolism, oxidative stress, and vitamin metabolism. Within disease states (early and late OA), subgroups of donors revealed distinct phenotypes. Synovial fluid metabolomic phenotypes exhibited increased inflammation (early and late OA), oxidative stress (late OA), or structural deterioration (early and late OA) in the synovial fluid.

CONCLUSION

These results revealed distinct metabolic phenotypes in human synovial fluid, provide insight into pathogenesis, represent novel biomarkers, and can move toward developing personalized interventions for subgroups of OA patients.

A field study of household attack rates and the effectiveness of macrolide antibiotics in reducing household transmission of pertussis

Bordetella pertussis (whooping cough) is an endemic, highly contagious bacterial respiratory infection, which is notifiable to Australian state and territory health departments. Between 2008 and 2011 there was a substantial outbreak in New South Wales with an initial increase in cases occurring in North Coast New South Wales from late 2007. During September and October 2011 the North Coast Public Health Unit conducted a household study of secondary attack rates to assess the effectiveness of pertussis vaccination as well as the timely use of antibiotics in preventing household transmission. At the time the study was commenced, notified cases included a large proportion of individuals with a documented history of vaccination against pertussis. We found lower attack rates amongst vaccinated compared with non-vaccinated subjects in all age groups, with the exception of the 5-11 years age group, who were also primarily responsible for the introduction of pertussis into the household. There was an increased risk of pertussis transmission from the household first primary case to contacts when antibiotic treatment was commenced later than 7 days after the onset of symptoms compared with within 7 days. This protective effect of timely antibiotic treatment in relation to transmission highlights the need to control for antibiotic treatment in field studies of pertussis. The benefits of timely diagnosis and use of antibiotics in preventing household transmission underscore the importance of early presentation and diagnosis of pertussis cases, particularly in households with susceptible occupants.

Regression to the mean using the disease activity score in eligibility and response criteria for prescribing TNF- inhibitors in adults with rheumatoid arthritis

OBJECTIVES

When patients with rheumatoid arthritis (RA) are selected to start TNF-alpha inhibitors on the basis of high disease activity scores (DAS), some of the fall in DAS will be due to regression to the mean (RTM). We have assessed the extent to which such RTM explains DAS improvements on TNF-alpha inhibitors in routine clinical practice.

METHODS

We retrospectively evaluated DAS28 scores that had been recorded as part of routine assessment for two RA cohorts. (i) Thirty-five patients receiving TNF-alpha inhibitors who had been assessed when starting TNF-alpha inhibitors, 9-21 months prior and 1.5-6 months post-treatment. (ii) One hundred and seventy-seven clinic patients assessed twice, a year apart in the years immediately before the introduction of TNF-alpha inhibitors.

RESULTS

In patients receiving TNF-alpha inhibitors, mean DAS fell 1.8 (95% confidence interval [CI] 1.3, 2.3) from baseline but only 0.9 (95% CI 0.4, 1.4) from the previous routine assessment. Twenty-four (69%) patients showed a fall in DAS of >1.2 from baseline but only 17 (49%) from the previous assessment. Regression analysis of results from the pre-biological era estimated that as much as 0.6 of the 1.8 apparent DAS response to TNF-alpha inhibitors might be accounted for by RTM.

CONCLUSIONS

Assessing change in DAS from commencement of biological therapy may overestimate response, due to the impact of RTM and fluctuation in disease. Adequacy of response might be better assessed by serial assessments and a wider range of patient-centred outcomes.

Touch-screen computer systems in the rheumatology clinic offer a reliable and user-friendly means of collecting quality-of-life and outcome data from patients with rheumatoid arthritis

OBJECTIVES

To investigate the feasibility of collecting rheumatoid arthritis (RA) patient self-administered outcome data using touch-screen computers in a routine out-patient clinic.

METHODS

Forty patients with RA completed the touch-screen and paper Rheumatoid Arthritis Quality of Life Questionnaire (RAQol) in the clinic and rated ease of use and preference. Forty-five others completed the Stanford Health Assessment Questionnaire (HAQ) and visual analogue scales (VASs) for pain, fatigue and global arthritis activity on touch screen and paper and a joint assessment on touch screen. They rated ease of use and willingness to complete the assessment again. Joints were independently assessed, and completion times and technical problems recorded.

RESULTS

No technical problems were encountered. The touch-screen RAQol took no longer to complete, was preferred by 64% (33% had no preference) and was rated significantly higher for ease of use (two-tailed P=0.003, n=40) even by computer naïve patients (two-tailed P=0.031, n=24). Intraclass correlation coefficients between methods were high for RAQol (0.986) and tender joint counts (0.918), and as high for the pain, fatigue and global activity (0.855, 0.741, 0.881) as for test-retest of the paper versions (0.865, 0.746, 0.863). Ninety-eight per cent rated the touch screen very/quite easy for HAQ and VAS, and 90% for joint assessment. Ninety-six per cent stated a willingness to complete the touch-screen assessment in clinic again.

CONCLUSIONS

Touch-screen questionnaires in the clinic can produce comparable results to paper, eliminate the need for data entry and afford immediate access to results. It is an acceptable, and in many cases a preferable, option to paper, regardless of age and previous experience of computers.

A simple extension to the Rheumatoid Arthritis Quality of Life Questionnaire (RAQol) to explore individual patient concerns and monitor group outcome in clinical practice

OBJECTIVES

To find out if the RAQol, if extended by a qualifying question on the level of concern associated with each item, can function both as a group outcome measure and as a useful tool to identify the concerns of individual patients.

METHODS

Thirty-seven rheumatoid arthritis (RA) patients completed the questionnaire before and after starting a biological therapy. One hundred and forty-five others receiving routine care completed it at baseline, weeks 12 and 13 with EuroQol VAS and questions on global arthritis impact and any other concerns. Reproducibility was assessed in all 59 participants whose condition remained stable between weeks 12 and 13.

RESULTS

The RAQol score was highly reproducible (intraclass correlation coefficient 0.986, n=59), reflected global RA impact (P = 0.000, n=140), negatively correlated with EuroQol VAS (Spearman coefficient=-0.639, two-tailed significance=0.000, n=142), responsive to biological therapy (two-tailed P= 0.000) and to increased global RA impact over 12 weeks (two-tailed P=0.012, n=37), and had high internal consistency (Cronbach's alpha=0.94, n=143). The number of issues of great concern and their percentage contribution to the RAQol score were related to global arthritis impact (P=0.000 for both) and reduced by a biological therapy (two-tailed P=0.000 and 0.001 respectively). The mean kappa for consistency in identifying each item as a concern was 0.801 (range 0.633-0.921).

CONCLUSIONS

Use of the 'extended' RAQol in clinical practice could provide a valid and sensitive score for monitoring group outcome and a comprehensive and consistent list of an individual's main issues of concern to assist assessment of needs in routine clinical practice.

Does the Stanford Health Assessment Questionnaire have potential as a monitoring tool for subjects with rheumatoid arthritis?

OBJECTIVE

To assist in the interpretation of the Stanford Health Assessment Questionnaire (HAQ) score changes for individual patients with rheumatoid arthritis (RA), by determining the minimum size of score change that can confidently be considered to reflect a significant change in disability from the patient's perspective.

METHOD

HAQ score changes were calculated for 40 clinic patients with RA who had reported no change to health in general over two months. These were considered to reflect both inconsistencies in questionnaire completion and any true but minor changes not considered significant enough by the patients to represent a change to their health in general. HAQ score changes over one year were also calculated for 207 clinic patients with RA.

RESULTS

The range within which 95% of score changes would be expected to lie in the absence of significant change was estimated as +/-0.48 points (+/-2SD of the score changes) and 80% within +/-0.31 points (+/-1.29SD). A chi(2) test showed no significant association between an HAQ score increase of >0.31 over one year and decline in health related to arthritis reported by the patient over the same period.

CONCLUSION

As a general guideline, an HAQ score needs to change by 0.48 points or more for 95% confidence that it reflects significant change (0.31 for 80% confidence). Although the value of HAQ as a group outcome measure is well established, this study questions the usefulness of monitoring individual HAQ scores in a clinical setting.

Renal failure due to 2,8-dihydroxyadenine urolithiasis

A four-year-old girl presented in renal failure due to dihydroxyadenine urolithiasis. Prior to this she had been fed a high purine macrobiotic diet, rich in pulses and grain. She was comatose, anuric, requiring peritoneal dialysis, and bilateral radiolucent renal calculi were revealed by ultrasonography and retrograde pyelography. 2,8-dihydroxyadenine stones were found at pyelolithotomy, renal biopsy revealed interstitial birefringent crystals, and a complete lack of adenine phosphoribosyl transferase (APRT) was found subsequently in erythrocyte lysates. APRT levels were initially falsely raised due to a blood transfusion on admission. The mother was shown to have heterozygote levels. The child was treated successfully with allopurinol, and a reduction in dietary purine but with only partial return of renal function.

Delayed separation of the umbilical cord, widespread infections, and defective neutrophil mobility

In six infants, from two families. the umbilical cords were still attached at 3 weeks of age. Five of these developed severe local and disseminated infections from which four died. Two of these children were tested, and both, including the survivor, had defective neutrophil mobility; in the survivor this was improved in vitro and in vivo by ascorbic acid. It is suggested that a primary genetic defect of a contractile protein could explain the association. The sixth child, with delayed cord separation but normal neutrophil mobility and no excess of infections, who has survived without special treatments, also has mastocytosis, apparently inherited independently.