Developing International Classification of Disease code definitions for the study of enteric infection sequelae in Canada

Background

Enteric infections and their chronic sequelae are a major cause of disability and death. Despite the increasing use of administrative health data in measuring the burden of chronic diseases in the population, there is a lack of validated International Classification of Disease (ICD) code-based case definitions, particularly in the Canadian context. Our objective was to validate ICD code definitions for sequelae of enteric infections in Canada: acute kidney injury (AKI); hemolytic uremic syndrome (HUS); thrombotic thrombocytopenic purpura (TTP); Guillain-Barré syndrome/Miller-Fisher syndrome (GBS/MFS); chronic inflammatory demyelinating polyneuropathy (CIDP); ankylosing spondylitis (AS); reactive arthritis; anterior uveitis; Crohn's disease, ulcerative colitis, celiac disease, erythema nodosum (EN); neonatal listeriosis (NL); and Graves' disease (GD).

Methods

We used a multi-step approach by conducting a literature review to identify existing validated definitions, a clinician assessment of the validated definitions, a chart review to verify proposed definitions and a final clinician review. We measured the sensitivity and positive predictive value (PPV) of proposed definitions.

Results

Forty studies met inclusion criteria. We identified validated definitions for 12 sequelae; clinicians developed three (EN, NL, GD). We reviewed 181 charts for 6 sequelae (AKI, HUS, TTP, GBS/MFS, CIDP, AS). Sensitivity (42.8%-100%) and PPV (63.6%-100%) of ICD code definitions varied. Six definitions were modified by clinicians following the chart review (AKI, TTP, GBS/MFS, CIDP, AS, reactive arthritis) to reflect coding practices, increase specificity or sensitivity, and address logistical constraints.

Conclusion

The multi-step design to derive ICD code definitions provided flexibility to identify existing definitions, to improve their sensitivity and PPV and adapt them to the Canadian context.

A Randomized Trial of a Multicomponent Intervention to Promote Medication Adherence: The Teen Adherence in Kidney Transplant Effectiveness of Intervention Trial (TAKE-IT)

BACKGROUND

Poor adherence to immunosuppressive medications is a major cause of premature graft loss among children and young adults. Multicomponent interventions have shown promise but have not been fully evaluated.

STUDY DESIGN

Unblinded parallel-arm randomized trial to assess the efficacy of a clinic-based adherence-promoting intervention.

SETTING & PARTICIPANTS

Prevalent kidney transplant recipients 11 to 24 years of age and 3 or more months posttransplantation at 8 kidney transplantation centers in Canada and the United States (February 2012 to May 2016) were included.

INTERVENTION

Adherence was electronically monitored in all participants during a 3-month run-in, followed by a 12-month intervention. Participants assigned to the TAKE-IT intervention could choose to receive text message, e-mail, and/or visual cue dose reminders and met with a coach at 3-month intervals when adherence data from the prior 3 months were reviewed with the participant. "Action-Focused Problem Solving" was used to address adherence barriers selected as important by the participant. Participants assigned to the control group met with coaches at 3-month intervals but received no feedback about adherence data.

OUTCOMES

The primary outcomes were electronically measured "taking" adherence (the proportion of prescribed doses of immunosuppressive medications taken) and "timing" adherence (the proportion of doses of immunosuppressive medications taken between 1 hour before and 2 hours after the prescribed time of administration) on each day of observation. Secondary outcomes included the standard deviation of tacrolimus trough concentrations, self-reported adherence, acute rejection, and graft failure.

RESULTS

81 patients were assigned to intervention (median age, 15.5 years; 57% male) and 88 to the control group (median age, 15.8 years; 61% male). Electronic adherence data were available for 64 intervention and 74 control participants. Participants in the intervention group had significantly greater odds of taking prescribed medications (OR, 1.66; 95% CI, 1.15-2.39) and taking medications at or near the prescribed time (OR, 1.74; 95% CI, 1.21-2.50) than controls.

LIMITATIONS

Lack of electronic adherence data for some participants may have introduced bias. There was low statistical power for clinical outcomes.

CONCLUSIONS

The multicomponent TAKE-IT intervention resulted in significantly better medication adherence than the control condition. Better medication adherence may result in improved graft outcomes, but this will need to be demonstrated in larger studies.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT01356277.

Absence of renal sequelae after childhood Escherichia coli O157:H7 gastroenteritis

Although a quarter of children who survive diarrhea-associated hemolytic uremic syndrome develop long-term renal sequelae, the prognosis of acute, self-limited Escherichia coli O157:H7 gastroenteritis has never been previously studied. Four years after a drinking water outbreak of E. coli O157:H7, we examined the risk of high blood pressure (>95th percentile expected for age, sex, and height), reduced kidney function, and microalbuminuria among previously healthy children and adolescents. Of the 951 participants, 313 were asymptomatic during the outbreak, 305 had moderate symptoms of acute gastroenteritis, and 333 had severe symptoms that necessitated medical attention. An additional 23 children who developed hemolytic uremic syndrome during the outbreak were excluded from this analysis. There were no differences in mean systolic blood pressure between those who had no, moderate, or severe symptoms of acute gastroenteritis during the outbreak (109, 110, and 107 mm Hg). Similarly, there were no group differences in diastolic blood pressure, estimated glomerular filtration rate, or random urine albumin to creatinine ratio (P ranged from 0.14 to 0.52), or in the adjusted relative risk of high blood pressure, a glomerular filtration rate <80 ml/min per 1.73 m(2), or microalbuminuria (P ranged from 0.23 to 0.89). Patients who presented to medical attention with gastroenteritis during this E. coli O157:H7 outbreak had an absence of renal sequelae 4 years later. With no existing data to support screening after self-limited E. coli O157:H7 gastroenteritis, we recommend that only those children who develop recognized features of hemolytic uremic syndrome be followed for long-term renal health.

Renal leiomyoma associated with Epstein-Barr virus in a pediatric transplant patient

Renal leiomyoma is a rare smooth muscle tumor of the kidney. An association between Epstein-Barr virus and smooth muscle tumors in immunocompromised patients recently has been recognized. We describe a pediatric renal transplant patient who developed an Epstein-Barr virus-associated renal leiomyoma in his transplant kidney 5 years posttransplantation. Possible factors involved in the tumor pathogenesis in our patient are discussed, including immunosuppression, growth hormone therapy, and Epstein-Barr virus induction.

Microalbuminuria three years after recovery from Escherichia coli O157 hemolytic uremic syndrome due to municipal water contamination

BACKGROUND

Knowledge of the long-term renal prognosis of diarrhea associated hemolytic uremic syndrome (HUS) is important for patient counseling and follow-up. However, estimates of long-term risk are highly variable, with previous studies not using a healthy control group.

METHODS

A municipal water system in the small rural town of Walkerton, Ontario, became contaminated with Escherichia coli O157:H7 in 2000. A cohort of 19 children who recovered from HUS was randomly age- and sex-matched to 38 children with no symptoms at the time of the outbreak. Both groups had detailed renal function testing 3 years after the outbreak, including a random urine albumin to creatinine, glomerular filtration rate estimated by Schwartz formula, and automated and manual blood pressure measurements.

RESULTS

There were no baseline differences between the groups with respect to age (mean 4.8 years, range 1 to 15), sex, or birth weight (mean 3.4 kg). In follow-up there were no differences between the groups in body surface area (mean 1.0 m(2)), or in the methods by which renal function was assessed. Compared to the group with no symptoms, patients with HUS demonstrated more microalbuminuria [32% vs. 5%, relative risk 4.8 (95% CI 1.1 to 22.0)], a nonsignificant trend toward lower GFR (124 vs. 134 mL/min per 1.73 m(2)), and no difference in blood pressure.

CONCLUSION

Children may demonstrate microalbuminuria 3 years after recovering from HUS. Longer follow-up is needed to determine if this finding has clinical relevance and utility.

Risk of hypertension and reduced kidney function after acute gastroenteritis from bacteria-contaminated drinking water

BACKGROUND

The long-term health consequences of acute bacterial gastroenteritis remain uncertain. We studied the risk of hypertension and reduced kidney function after an outbreak of acute gastroenteritis due to contamination of a regional drinking water supply with Escherichia coli O157:H7 and Campylobacter species.

METHODS

A total of 1958 adults with no known history of hypertension or kidney disease before the outbreak participated in a long-term follow-up study. Of the participants, 675 had been asymptomatic during the outbreak, 909 had had moderate symptoms of acute self-limited gastroenteritis, and 374 had had severe symptoms that necessitated medical attention. The outcomes of interest were a diagnosis of hypertension or the presence of reduced kidney function and albuminuria during the follow-up period.

RESULTS

After a mean follow-up of 3.7 years after the outbreak, hypertension was diagnosed in 27.0% of participants who had been asymptomatic during the outbreak and in 32.3% and 35.9% of those who had had moderate and severe symptoms of acute gastroenteritis respectively (trend p = 0.009). Compared with the asymptomatic participants, those with moderate and severe symptoms of gastroenteritis had an adjusted relative risk of hypertension of 1.15 (95% confidence interval [CI] 0.97-1.35) and 1.28 (95% CI 1.04-1.56) respectively. A similar graded association was seen for reduced kidney function, defined as the presence of an estimated glomerular filtration rate below 60 mL/min per 1.73 m2 (trend p = 0.03). No association was observed between gastroenteritis and the subsequent risk of albuminuria.

INTERPRETATION

Acute bacterial gastroenteritis necessitating medical attention was associated with an increased risk of hypertension and reduced kidney function 4 years after infection. Maintaining safe drinking water remains essential to human health, as transient bacterial contaminations may have implications well beyond a period of acute self-limited illness.