Validation of Administrative Osteoarthritis Diagnosis Using a Clinical and Radiological Population-Based Cohort

"Application of five different strategies to define a cohort of patients with knee osteoarthritis in a large primary care database"

BACKGROUND

Electronic health records (EHR) are frequently used for epidemiological research including drug utilisation studies in a defined population such as the population with knee osteoarthritis (KOA). We sought to describe the process of defining a cohort of patients with KOA from a large UK primary care database and estimate the annual incidence of diagnosed KOA between 2000 and 2015.

METHOD

This was a retrospective study using data from the clinical practice research datalink (CPRD). CPRD is a large primary care longitudinal electronic medical records' database that contains anonymous records of patients from general practices across United Kingdom. Five different cohort definition strategies were applied including symptoms-based or diagnosis-based strategies or a combination of both. To validate results, the annual incidence of KOA was estimated and compared to published data.

RESULTS

The study defined 898,690 patients when symptoms-based strategy was applied, 137,541 patients when diagnosis based and 83,294 when a combination of both strategies were applied. The final cohort was defined using a diagnosis-based strategy that avoided overestimation (with symptoms-based definition) or underestimation (with a combination of symptoms and diagnosis). The incidence of KOA ranged from 1.33 per 1000 CPRD registrants in 2000, 1.76 in 2008 and 1.45 patients in 2015.

CONCLUSION

This study logically/sensibly defined a cohort of patients with diagnosed KOA through the application of several strategies. This was an essential step to avoid subsequent over or underestimation of the prevalence of drug utilisation and the associated adverse clinical outcomes within primary care patients with KAO.

Increased risk of osteoarthritis in patients with atopic disease

OBJECTIVES

To determine the incidence of osteoarthrits (OA) in patients with atopic disease compared with matched non-exposed patients.

METHODS

We conducted a retrospective cohort study with propensity score matching using claims data from Optum's de-identified Clinformatics Data Mart (CDM) (January 2003 to June 2019) and electronic health record data from the Stanford Research Repository (STARR) (January 2010 to December 2020). We included adult patients without pre-existing OA or inflammatory arthritis who were exposed to atopic disease or who were non-exposed. The primary outcome was the development of incident OA.

RESULTS

In Optum CDM, we identified 117 346 exposed patients with asthma or atopic dermatitis (mean age 52 years; 60% female) and 1 247 196 non-exposed patients (mean age 50 years; 48% female). After propensity score matching (n=1 09 899 per group), OA incidence was higher in patients with asthma or atopic dermatitis (26.9 per 1000 person-years) compared with non-exposed patients (19.1 per 1000 person-years), with an adjusted odds ratio (aOR) of 1.58 (95% CI 1.55 to 1.62) for developing OA. This effect was even more pronounced in patients with both asthma and atopic dermatitis compared with non-exposed patients (aOR=2.15; 95% CI 1.93 to 2.39) and in patients with asthma compared with patients with chronic obstructive pulmonary disease (aOR=1.83; 95% CI 1.73 to 1.95). We replicated our results in an independent dataset (STARR), which provided the added richness of body mass index data. The aOR of developing OA in patients with asthma or atopic dermatitis versus non-exposed patients in STARR was 1.42 (95% CI 1.36 to 1.48).

CONCLUSIONS

This study demonstrates an increased incidence of OA in patients with atopic disease. Future interventional studies may consider targeting allergic pathways for the prevention or treatment of OA.

Population-Based Analysis of Nonsteroidal Anti-inflammatory Drug Prescription in Subjects With Chronic Kidney Disease

Background

Pain is a prevalent symptom experienced by patients with chronic kidney disease (CKD) and appropriate management of pain is an important element of comprehensive care. Nonsteroidal anti-inflammatory drugs (NSAID) are known to be nephrotoxic in persons with CKD.

Objective

This study examined the pattern of NSAID prescribing practices in a population based-cohort of patients with CKD.

Design

Retrospective cohort study using linked population-based health care data.

Setting

Entire province of Alberta, Canada.

Participants

All adults in Alberta with eGFR defined CKD G3 or greater between 2009 and 2017 were included.

Measurements

CKD was defined using at least 2 outpatient serum creatinine (SCr) greater than 90 days apart; the date of second SCr measurement was used as index date. We determined the incidence of hyperkalemia using the peak serum potassium. Prescription drug information was obtained from the Pharmaceutical Information Network (PIN) database.

Methods

All patients were followed from the index date until March 31, 2019, with a minimum follow-up of 2 years. Prescription drug information and the follow-up laboratory testing of serum creatinine and serum potassium were obtained. Patients with kidney failure defined as eGFR < 15 mL/min per 1.73 m², receiving chronic dialysis, or prior kidney transplant at baseline were excluded.

Results

A total of 170 574 adults (mean age 76.3; 44% male) with CKD were identified and followed for a median of 7 years; 27% were dispensed at least 1 NSAID prescription. While there was a trend toward fewer prescriptions in patients with more advanced CKD (P < .001), 16% of those with CKD G4 were prescribed an NSAID. Primary care providers provided 79% of the prescriptions. Among NSAID users, 21% had a follow-up serum creatinine (SCr) within 30 days of the index prescription.

Limitations

Data collected were from clinical and administrative databases not created for research purposes. The study cohort is limited to subjects who sought medical care and had a serum creatinine measurement obtained. Measurement of NSAID use is limited to those who were dispensed a prescription, over-the-counter NSAIDs use is not captured.

Conclusions

Despite guidelines advocating cautious use of NSAIDs in patients with CKD, this study indicates that there is a discrepancy from best practice recommendations. Effective strategies to better support and educate prescribers, as well as patients, may help reduce inappropriate prescribing and adverse events.

Association of tramadol with all-cause mortality, cardiovascular diseases, venous thromboembolism, and hip fractures among patients with osteoarthritis: a population-based study

Background

The use of tramadol among osteoarthritis (OA) patients has been increasing rapidly around the world, but population-based studies on its safety profile among OA patients are scarce. We sought to determine if tramadol use in OA patients is associated with increased risks of all-cause mortality, cardiovascular diseases (CVD), venous thromboembolism (VTE), and hip fractures compared with commonly prescribed nonsteroidal anti-inflammatory drugs (NSAIDs) or codeine.

Methods

Using administrative health datasets from British Columbia, Canada, we conducted a sequential propensity score-matched cohort study among all OA patients between 2005 and 2013. The tramadol cohort (i.e., tramadol initiation) was matched with four comparator cohorts (i.e., initiation of naproxen, diclofenac, cyclooxygenase-2 [Cox-2] inhibitors, or codeine). Outcomes are all-cause mortality, first-ever CVD, VTE, and hip fractures within the year after the treatment initiation. Patients were followed until they either experienced an event, left the province, or the 1-year follow-up period ended, whichever occurred first. Cox proportional hazard models were used to estimate hazard ratios after adjusting for competing risk of death.

Results

Overall, 100,358 OA patients were included (mean age: 68 years, 63% females). All-cause mortality was higher for tramadol compared to NSAIDs with rate differences (RDs/1000 person-years, 95% CI) ranging from 3.3 (0.0–6.7) to 8.1 (4.9–11.4) and hazard ratios (HRs, 95% CI) ranging from 1.2 (1.0–1.4) to 1.5 (1.3–1.8). For CVD, no differences were observed between tramadol and NSAIDs. Tramadol had a higher risk of VTE compared to diclofenac, with RD/1000 person-years (95% CI) of 2.2 (0.7–3.7) and HR (95% CI) of 1.7 (1.3–2.2). Tramadol also had a higher risk of hip fractures compared to diclofenac and Cox-2 inhibitors with RDs/1000 person-years (95% CI) of 1.9 (0.4–3.4) and 1.7 (0.2–3.3), respectively, and HRs (95% CI) of 1.6 (1.2–2.0) and 1.4 (1.1–1.9), respectively. No differences were observed between tramadol and NSAIDs for all events.

Conclusions

OA patients initiating tramadol have an increased risk of mortality, VTE, and hip fractures within 1 year compared with commonly prescribed NSAIDs, but not with codeine.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02764-3.

Validation of knee osteoarthritis case identification algorithms in a large electronic health record database

Purpose:

To facilitate studies of knee osteoarthritis (OA) in large databases, case finding algorithms with high levels of diagnostic performance are needed.

Methods:

From a UK general practitioner (GP) practice derived database, we selected adults ages 40–90 years meeting algorithms that included various combinations of codes for knee OA or knee pain and imaging. The GP for each patient was mailed a questionnaire to assess the cause of knee pain and provide knee x-ray and/or MRI findings. We considered knee pain with x-ray and/or MRI findings consistent with OA the gold standard. We calculated positive predictive values (PPV) and sensitivity for case identification algorithms.

Results:

Of 100 questionnaires sent, 93 were returned; we excluded 8 subjects who had other rheumatic disorders or total knee replacements. Among those with one code for OA, the PPV was 64% (95% CI = 49%–79%) and it increased to 92% (95% CI = 76%–100%) when two or more OA codes over six months were required. The increase in PPV was accompanied by a drop in sensitivity from 44% (95% CI = 31%–57%) to 19% (95% CI = 9%–30%). Use of one pain code yielded similar results to use of one OA code. Requiring two or more knee pain codes over six months yielded a PPV of 68% (95% CI = 49%–88%) and sensitivity of 26% (95% CI = 15%–38%).

Discussion:

A case identification algorithm requiring two or more knee OA codes yielded the highest PPV at the cost of reduced sensitivity. Tradeoffs between PPV and sensitivity will need to be weighed alongside study goals when selecting a case identification algorithm.

Osteoarthritis care and risk of total knee arthroplasty among medicare beneficiaries

OBJECTIVE

To examine health care utilization among patients with knee osteoarthritis and test if utilization differed among residents of regions with high and low rates of total knee arthroplasty (TKA).

DESIGN

This was a retrospective cohort study of U.S. Medicare beneficiaries in 2005 - 2010 with knee osteoarthritis. Health care utilization for knee complaints, including rates of physician visits, physical therapy, knee injections and arthroscopy were abstracted from claims files until TKA or the end of study in 2015. Utilization was compared among beneficiaries who lived in regions with high or low rates of TKA.

RESULTS

Among 988,570 beneficiaries with knee osteoarthritis, 327,499 beneficiaries (33.1%) had TKA during follow-up (median 5.6 years). Higher rates of visits for knee complaints were associated with increased risks of arthroplasty, while use of physical therapy, specialist care, and intra-articular treatments were associated with lower risks. Frequency of TKA varied from 26.4% in the lowest quintile region to 42.1% in the highest quintile. Rates of physician visits, physical therapy, specialist care, and use of intra-articular injections varied inversely with arthroplasty quintile. For example, physical therapy was used by 32.5% of beneficiaries in the lowest quintile region and 23.6% in the highest quintile region. Physical therapy was associated with lower TKA rates across all quintiles.

CONCLUSIONS

Dedicated non-surgical osteoarthritis care was infrequently used by elderly Americans with knee osteoarthritis. Non-surgical care was more common in regions with low rates of TKA, suggesting reciprocal emphasis on medical versus surgical treatment across regions.

Time-trends in cocaine, hallucinogen, amphetamine, and sedative/anxiolytic/hypnotic use disorder hospitalizations in rheumatic diseases: a national time-trends study

Musculoskeletal diseases (MSDs) are common in the general population, frequently associated with pain, functional limitation, and reduction in quality of life. Similarly, drug/substance use disorders are common in the general population. Recently, opioid drug use disorder has gained a lot of attention as a public health problem. To our knowledge, limited data exist regarding the non-opioid drug/substance use disorders in musculoskeletal diseases. This study's objective was to examine the frequency and rates of common drug/substance use disorder hospitalizations in five MSDs, namely gout, osteoarthritis, fibromyalgia, rheumatoid arthritis, and low back pain. This was achieved by using the diagnostic codes for cocaine, hallucinogen, amphetamine, or ASH use disorder hospitalization in five MSDs in the US National Inpatient Sample from 1998 to 2014. Cocaine, hallucinogen, amphetamine, or ASH use disorder hospitalizations per 1 million NIS total hospitalizations for five MSDs in 2013-2014 were as follows, respectively: gout, 10.2, 0.1, 2.8, and 1.5; osteoarthritis, 21.4, 0.4, 5.9, and 7.7; fibromyalgia, 5.5, 0.1, 2.0, and 2.3; rheumatoid arthritis, 8.7, 0.4, 4.5, and 7.7, and low back pain, 16.2, 0.5, 7.3, and 7.5. The frequency and the rate of each drug use disorder hospitalization increased in each of the five MSDs from 1998 to 2014. Key Points • Cocaine or hallucinogen use disorder hospitalization rates increased several-fold in people with MSDs from 1998 to 2014. • Amphetamine and anxiolytic, sedative, or hypnotic (ASH) use disorder hospitalization rates increased 9- to 23-fold vs. 4- to 7-fold, respectively, in people with common MSDs in the USA from 1998 to 2014.

β-blocker prescription is associated with lower cumulative risk of knee osteoarthritis and knee pain consultations in primary care: a propensity score matched cohort study

Objectives

To examine the association between β-blocker prescription and first primary-care consultation for knee OA, hip OA, knee pain and hip pain.

Methods

Data source: Clinical Practice Research Datalink. Participants aged ≥40 years in receipt of new oral β-blocker prescriptions were propensity score (PS) matched to an unexposed control. Cox proportional hazard ratios (HRs) and 95% CIs were calculated, and adjusted for non-osteoporotic fractures, number of primary-care consultations for knee or hip injury, and, the number of primary-care consultations, out-patient referrals and hospitalizations in the 12 months preceding cohort entry. Analysis was stratified according to β-blocker class and for commonly prescribed drugs. P < 0.05 was considered statistically significant.

Results

A total of 111 718 β-blocker–exposed participants were 1:1 PS matched to unexposed controls. β-blocker prescription was associated with reduced cumulative risk of knee OA, knee pain, and hip pain consultations [with a HR (95% CI) of 0.90 (0.83, 0.98), 0.88 (0.83, 0.92) and 0.85 (0.79, 0.90), respectively]. Propranolol and atenolol were associated with a lower incidence of knee OA and knee pain consultations with a HR of between 0.78 and 0.91. β-blockers were associated with reduced incidence of consultation for large-joint lower-limb OA/pain as a composite outcome, defined as the earliest of knee OA, knee pain, hip OA or a hip pain consultation [with a HR (95% CI) of 0.87 (0.84, 0.90)].

Conclusion

Commonly used β-blockers have analgesic properties for musculoskeletal pain. Atenolol might be a therapeutic option for OA and cardiovascular co-morbidities in which β-blockers are indicated, while propranolol may be suitable for people with co-morbid anxiety. A confirmatory randomized controlled trial is needed before clinical practice is changed.

More Severe Radiographic Osteoarthritis Is Associated With Increased Improvement in Patients' Health State Following a Total Knee Arthroplasty

BACKGROUND

To assess whether preoperative radiological severity of osteoarthritis (OA) is related to the level of improvement in patients' health state measured 1 year after total knee arthroplasty (TKA).

METHODS

Radiographic severity of OA was graded using the Kellgren-Lawrence (KL) classification. Two independent observers were blinded to patients' outcome scores. Health-related quality of life was measured using EQ-5D-3L preoperatively and at 12-month follow-up. The 5 dimensions of the EQ-5D were converted into a health state index score. The association between KL grade and improvement in health state score was analyzed using multiple linear regression.

RESULTS

Among 156 consecutive patients (68% females, mean age 69 years) who underwent primary TKA, 3 knees (2%) were classified as KL grade 2, 115 as KL grade 3 (74%), and 38 as KL grade 4 (24%). Follow-up rate was 77%. There was substantial intra-rater and inter-rater agreement (Cohen's kappa = 0.80 and 0.79). Most patients (64%) had clinically significant improvement in their health state score 1 year after TKA. However, after adjusting for relevant covariates, patients with severe OA (KL grade 4) were found to have significantly more improvement in their health state score than patients with mild or moderate OA (KL grade 2 or 3, respectively). Separate analysis of the 5 EQ-5D dimensions showed that the KL group differences were most evident in the "usual activities" and "pain/discomfort" dimensions.

CONCLUSION

Patients with severe OA have significantly more improvement in their usual activities and pain/discomfort 1 year after TKA than patients with less severe OA.

Time Trends in Opioid Use Disorder Hospitalizations in Gout, Rheumatoid Arthritis, Fibromyalgia, Osteoarthritis, and Low Back Pain

OBJECTIVE

To examine opioid use disorder (OUD)-related hospitalizations and associated healthcare utilization outcomes in people with 5 common musculoskeletal diseases (MSD).

METHODS

We used the US National Inpatient Sample (NIS) data from 1998 to 2014 to examine the rates of OUD hospitalizations (per 100,000 NIS claims overall), time trends, and outcomes in 5 common rheumatic diseases: gout, rheumatoid arthritis (RA), fibromyalgia (FM), osteoarthritis (OA), and low back pain (LBP).

RESULTS

OUD hospitalization rate per 100,000 total NIS claims in 1998-2000 vs 2015-2016 (and increase) were as follows: gout, 0.05 vs 1.88 (36-fold); OA, 0.68 vs 10.22 (14-fold); FM, 0.53 vs 6.98 (12-fold); RA, 0.30 vs 3.16 (9.5-fold); and LBP, 1.17 vs 7.64 (5.5-fold). The median hospital charges and hospital stays for OUD hospitalizations were as follows: gout, $18,363 and 2.5 days; RA, $17,398 and 2.4 days; FM, $15,772 and 2.1 days; OA, $16,795 and 2.4 days; and LBP, $13,722 and 2.0 days. In-hospital mortality rates ranged from 0.9% for LBP and FM to 1.7% for gout with OUD hospitalizations. Compared to those without each MSD, age-, sex-, race-, and income-adjusted total hospital charges (inflation-adjusted) for OUD hospitalizations with each rheumatic disease were as follows: gout, $697 higher; OA, $4759 lower; FM, $2082 lower; RA, $1258 lower; and LBP, $4944 lower.

CONCLUSION

OUD hospitalizations increased in all 5 MSD studied, but the rate of increase differed. Awareness of these OUD hospitalization trends in 5 MSD among providers, policy makers, and patients is important. Development and implementation of interventions, policies, and practices to potentially reduce OUD-associated effects in people with rheumatic diseases is needed.

Hospitalized Infections in People With Osteoarthritis: A National US Study

OBJECTIVE

To study the incidence, time trends, and outcomes of serious infections in people with osteoarthritis (OA).

METHODS

We used 1998-2016 US National Inpatient Sample (NIS) data. Using recommended weights, we examined the epidemiology of 5 types of serious infections requiring hospitalization in people with OA (opportunistic infections [OIs], skin and soft tissue infections [SSTIs], urinary tract infections [UTIs], pneumonia, and sepsis/bacteremia). We performed multivariable-adjusted logistic regression analyses to analyze factors associated with healthcare utilization (hospital charges, length of hospital stay, discharge to nonhome setting), and in-hospital mortality.

RESULTS

Of all serious infection hospitalizations, 46,708,154 were without OA and 3,258,416 had OA. People with OA were 16.4 years older, more likely to be female (52% vs 65%), White (59% vs 70%), have a Deyo-Charlson Comorbidity Index (DCCI) ≥ 2 (42% vs 51%), receive Medicare (54% vs 80%), and less likely to receive care at an urban teaching hospital (45% vs 39%). Serious infection rates per 100,000 NIS hospitalizations increased from the study period of 1998-2000 to 2015-2016: OI (from 4.5 to 7.2); SSTI (from 48.4 to 145.9); UTI (from 8.4 to 104.6); pneumonia (from 164.0 to 224.3); and sepsis (from 39.4 to 436.3). In multivariable-adjusted analyses, older age, higher DCCI, sepsis, northeast region, urban hospital, and medium or large hospital bed size were significantly associated with higher healthcare utilization outcomes and in-hospital mortality; Medicaid insurance, non-White race, and female sex were significantly associated with higher healthcare utilization.

CONCLUSION

Serious infection rates have increased in people with OA. Association of demographic, clinic, and hospital variables with serious infection outcomes identifies potential targets for future interventions.

Improving measurement of binary covariates in claims data: A simulation study

PURPOSE

When investigators have two claims-based definitions for a binary confounder, it is unclear whether to prefer the more sensitive or more specific definition. Our objective was to compare adjusting for the sensitive or specific definition alone vs two novel approaches combining both definitions: a "two-algorithm indicator" and a "two-algorithm restriction" approach.

METHODS

Each simulated patient had a binary exposure, outcome, and confounder. We created two nested, misclassified versions of the confounder using validated heart failure definitions. The sensitive definition had a sensitivity/specificity of 0.98/0.83, while the specific definition had a sensitivity/specificity of 0.77/0.99. Patients were classified into 3 groups: group 0 did not meet either definition, group 1 met the sensitive but not specific definition, and group 2 met both. The two-algorithm indicator approach adjusted using indicators for groups 1 and 2, while the two-algorithm restriction approach excluded patients in group 1 and adjusted using an indicator for group 2. Adjusted exposure odds ratios (ORs) were estimated for each approach using logistic regression.

RESULTS

The crude OR was 1.33 (95% CI, 1.07-1.63). Adjusting for the specific or sensitive definitions resulted in ORs of 1.09 (95% CI, 0.87-1.35) and 1.14 (95% CI, 0.91-1.40). The two-algorithm indicator method returned an OR of 1.07 (95% CI, 0.86-1.33). The two-algorithm restriction approach returned an OR of 1.02 (95% CI, 0.79-1.29) but excluded 20% of the cohort.

CONCLUSIONS

The two-algorithm indicator approach may improve adjustment for claims-based confounders by returning a point estimate at least as unbiased as the better of the two component definitions.

Causal Factors for Knee, Hip, and Hand Osteoarthritis: A Mendelian Randomization Study in the UK Biobank

OBJECTIVE

There is no curative treatment for osteoarthritis (OA), which is the most common form of arthritis. This study was undertaken to identify causal risk factors of knee, hip, and hand OA.

METHODS

Individual-level data from 384,838 unrelated participants in the UK Biobank study were analyzed. Mendelian randomization (MR) analyses were performed to test for causality for body mass index (BMI), bone mineral density (BMD), serum high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglyceride levels, type 2 diabetes, systolic blood pressure (BP), and C-reactive protein (CRP) levels. The primary outcome measure was OA determined using hospital diagnoses (all sites, n = 48,431; knee, n = 19,727; hip, n = 11,875; hand, n = 2,330). Odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated.

RESULTS

MR analyses demonstrated a robust causal association of genetically determined BMI with all OA (OR per SD increase 1.57 [95% CI 1.44-1.71]), and with knee OA and hip OA, but not with hand OA. Increased genetically determined femoral neck BMD was causally associated with all OA (OR per SD increase 1.14 [95% CI 1.06-1.22]), knee OA, and hip OA. Low systolic BP was causally associated with all OA (OR per SD decrease 1.55 [95% CI 1.29-1.87]), knee OA, and hip OA. There was no evidence of causality for the other tested metabolic factors or CRP level.

CONCLUSION

Our findings indicate that BMI exerts a major causal effect on the risk of OA at weight-bearing joints, but not at the hand. Evidence of causality of all OA, knee OA, and hip OA was also observed for high femoral neck BMD and low systolic BP. However, we found no evidence of causality for other metabolic factors or CRP level.

Validation of algorithms to identify knee osteoarthritis patients in the claims database

BACKGROUND

To identify knee osteoarthritis (OA) patients among OA patients in the claims database.

METHODS

All patients with OA diagnostic codes for any sites (M15 to M19) in 2014 were recruited from a single academic referral hospital. After excluding patients who had inflammatory arthritis or were less than 50 years of age, we identified data for the overall OA population. Radiographic knee OA of Kellgren and Lawrence grades ≥2 is considered the gold standard for knee OA, and we evaluated the sensitivity, specificity, and positive predictive value (PPV) of three operational definitions using the diagnostic codes in the claims database. The operational definitions were: (1) gonarthrosis (M17); (2) any site of OA (M15 to M19) with knee X-ray; and (3) (1) or (2).

RESULTS

A total of 7959 OA patients were included in this study of whom 74.5% were women. The PPV of gonarthrosis (M17) was 0.67 (95% CI 0.65-0.69), and sensitivity was 0.44 (95% CI 0.42-0.46). The PPV and sensitivity of any OA site (M15 to M19) with knee X-ray were 0.65 (95% CI 0.62-0.67), and 0.37 (95% CI 0.35-0.39), respectively. When knee OA was defined as satisfying either of the two above definitions, PPV was 0.63 (95% CI 0.62-0.65) and sensitivity 0.55 (95% CI 0.53-0.57).

CONCLUSIONS

Knee OA patients can be identified in a claims database using the algorithms of gonarthrosis (M17) or any site of OA (M15 to M19) with a performed knee X-ray.

Underrecording of osteoarthritis in United Kingdom primary care electronic health record data

Purpose

Primary care electronic health records are increasingly used to estimate the occurrence of osteoarthritis (OA). We aimed to estimate the extent and trend over time of underrecording of severe OA patients in UK primary care electronic health records using first primary total hip and knee replacements (THR/TKR) - >90% of which are performed for OA - as the reference population.

Patients and methods

We identified patients with a first primary THR or TKR recorded in the UK Clinical Practice Research Datalink between 2000 and 2015. We then searched for a diagnostic/problem code for OA up to 10 years prior to THR/TKR using 3 definitions: "diagnosed OA (joint-specific)," "diagnosed OA (any joint)," "clinical OA" (diagnosed OA or relevant peripheral joint pain symptom code).

Results

Among 34,299 THR patients identified, 28.1%, 53.4%, and 74.4% had a prior record of diagnosed OA (hip), diagnosed OA (any), and clinical OA, respectively. Among 47,588 TKR patients, the corresponding figures were, 25.5% (diagnosed OA [knee]), 43.7%, and 74.8%. In the UK Clinical Practice Research Datalink, the proportion of patients with prior recorded OA decreased between 2000 and 2015.

Conclusion

An increasing trend of underrecording of OA or joint pain among patients with THR or TKR (severe OA patients) between 2000 and 2015 was identified. An underestimate health care demand could be derived based on consultation incidence and prevalence of OA from electronic health record data that relies on osteoarthritis diagnostic codes. Further studies are warranted to investigate the validity of OA or joint pain recorded in primary care settings, which might be used to correct the consultation incidence and prevalence of OA.

Zhuangguguanjie formulation protects articular cartilage from degeneration in joint instability-induced murine knee osteoarthritis

Zhuangguguanjie formulation (ZG) can provide noticeable relief from joint pain in patients suffering from knee osteoarthritis (OA). However, the underlying mechanism has not been fully described. Male C57BL/6 mice were administered either ZG or normal saline (NS) following surgical destabilization of the medial meniscus (DMM). At weeks 4, 6 and 8 (post-surgery), knee joints were harvested and assessed with Safranin-O staining. Blood serum was collected and tested. In vitro analysis was carried out to evaluate the effects of ZG on the expression of the OA-related genes. DMM mice indicated reduced cartilage destruction and lower blood serum biomarkers of OA (COMP1 and CTX-1) following ZG treatment. Moreover, the femoral condyle and tibial plateau histological scores were significantly reduced following ZG treatment of the DMM mice. ZG could markedly downregulate the expression of OA-related genes namely, ADAMTS5, MMP3 and MMP13, while it simultaneously upregulated collagen II as demonstrated by in vitro assays. Moreover, chondrocyte apoptosis was significantly decreased following ZG treatment. These results may be caused by the up-regulation of p-AKT expression levels, since the anti-apoptotic effects of ZG can be blocked by treatment with an AKT inhibitor. ZG is capable of preventing and/or reducing the progression of OA by inhibiting chondrocyte apoptosis via the p-AKT/Caspase 3 pathway.

The molecular mechanism of treating osteoarthritis with dipsacus saponins by inhibiting chondrocyte apoptosis

The present study aimed to determine the molecular mechanism of treating osteoarthritis with dipsacus saponins by inhibiting the apoptosis of chondrocytes. A total of 30 New Zealand rabbits were randomly divided into 2 groups: A control group and a model group. The osteoarthritis model was established using the HULTH method. The success of the model establishment was determined by pathological morphology and measurement of inflammatory cytokine levels. Chondrocytes were isolated and divided into 4 groups treated with varying concentrations of dipsacus saponins: 0, 25, 50 and l00 µg/l dipsacus saponins. Cell cycle distribution was analyzed using flow cytometry. Changes in cyclin D1, cyclin-dependent kinase 4 (CDK4) and p21 expression were detected by western blotting and changes in the levels of Bcl-2, Bax, caspase-3 and caspase-9 mRNA were detected using reverse transcription-quantitative polymerase chain reaction. The osteoarthritis model was established successfully, indicated by a significant increase in the levels of IL-1β, IL-6 and TNF-α in the model group (P<0.05) compared with the control group. The viability of the chondrocytes increased following treatment with dipsacus saponins in a concentration-dependent manner. The number of chondrocytes in the G0/G1 phase decreased in the 50 and l00 µg/l groups while the number of chondrocytes in the G2/M phase increased in the 50 and l00 µg/l groups. Levels of cyclin D1 and CDK4 expression increased following treatment with dipsacus saponins. Levels of Bax, caspase-3 and caspase-9 expression decreased while Bcl-2 levels increased following treatment with dipsacus saponins. The viability of chondrocytes increased following treatment with dipsacus saponins in a concentration-dependent manner. Thus, dipsacus saponins inhibited the apoptosis of chondrocytes by up-regulating Bcl-2 and down-regulating caspase-9, caspase-3 and Bax expression.