This guideline provides recommendations for the investigation, evaluation, and management of adults at risk of or with known chronic kidney disease (CKD). These recommendations and treatment targets may not be appropriate in all cases because many patients with CKD are complex due to older age and comorbidities. Communication between primary care providers and specialists is strongly encouraged.- Identify high-risk patient groups for evaluation of CKD: diabetes, hypertension, cardiovascular disease, family history, high risk ethnicity (Indigenous peoples, Pacific Islanders, African, Asian, and South Asian descent), history of acute kidney injury (AKI). - Screen high-risk patients using eGFR and uACR. Confirm abnormal test results with a repeat measurement and obtain urinalysis. - Determine likely cause of kidney disease where possible. The cause of CKD has important implications for the risk of end stage renal disease (ESRD) and other complications. - The three dimensions of Cause, eGFR and Albuminuria (CGA) are all important in developing a management plan. - Prompt advice from local internists, local nephrologists or the RACE Line is available to assist in determining the need for and timing of referral.# 
Background CKD is associated with other common chronic diseases such as diabetes, hypertension, and cardiovascular disease (CVD) 1 and an estimated 1:10 British Columbians has some form of significant kidney disease. 2 CKD markedly increases the risk of: cardiovascular disease, adverse drug reactions, acute kidney injury and prolonged hospital admissions.  Patients with CKD have a risk of progression to end stage renal disease (ESRD), often requiring dialysis or kidney transplantation. 6,9, Most patients with chronic kidney disease die from other comorbidities before they progress to kidney failure. The outcome of many patients who go on to dialysis remains poor with 10 percent annual mortality; the overall 5 year survival rate is worse than that of most cancers. 3 Evidence clearly indicates that control of hypertension and proteinuria can prevent or postpone kidney function decline. 4 -12 This underscores the importance of early detection, evaluation and management of individuals with kidney disease.

# Definition
CKD is defined as an abnormality of kidney structure or function that is present for greater than 3 months. 13 The two key parameters for classification are estimated glomerular filtration rate (eGFR) and urine albumin to creatinine ratio (uACR). eGFR is the best marker for kidney function and is calculated from creatinine. All labs in British Columbia (BC) automatically report eGFR when creatinine is ordered. Note: the recommended equations for eGFR may change over time and are estimates only. Refer to page 3 for more information.
For diagnostic purposes, other evidence of kidney damage includes: urine abnormalities such as hematuria; structural problems on imaging studies e.g., polycystic kidneys on ultrasound; histological findings on kidney biopsy.

# Etiology
The two most common causes of CKD are hypertension and diabetes and they often co-exist. 13 Even if the cause seems obvious (e.g., diabetes), the possibility of a serious underlying primary renal disorder (e.g., glomerulonephritis) must be considered in patients with:
- Abnormal urinalysis, (e.g., proteinuria, hematuria, cellular casts). Note: hyaline casts are normal.
- Rapid sustained decline in kidney function (change in eGFR > 10-15%/year) despite remedy of reversible precipitants (e.g., volume contraction, febrile illness, medications). - Constitutional symptoms suggesting systemic illness.
- Sudden or severe onset of symptoms (e.g., edema unrelated to heart or liver disease).  

# Risk Factors and Screening
The following populations are at increased risk for CKD and should be screened:
- Diabetes - Hypertension - Cardiovascular disease (CVD)
- Prior acute kidney injury (AKI)
- Family history of kidney disease (e.g., parent or sibling)
- Specific high-risk ethnic groups: Indigenous peoples, Pacific Islanders, African Asian, and South Asian descent Note: Older age alone is not a reason for screening.
At-risk populations should be screened every 1-2 years depending upon clinical circumstances (e.g., annually for individuals with diabetes) using:
- eGFR - urinalysis (dipstick)- - urine ACR - review of risk factors *Note: urine microscopy is not needed for screening.

# Diagnosis
CKD cannot be diagnosed with one isolated abnormal measurement of eGFR or urine ACR.

# Estimated GFR (eGFR) Values and Interpretation
- Values of > 60 mL/min per 1.73m 2 without other markers of kidney disease (albuminuria, hematuria, structural abnormalities) do not indicate CKD. - Values of < 60 mL/min per 1.73m 2 which are persistent (present for  3 months) are diagnostic of CKD.
- A single isolated measurement < 60 mL/min does not satisfy diagnostic criteria for CKD, but could reflect reduced kidney function and requires confirmatory testing. - In patients with a new unexpected finding of reduced eGFR, the test should be repeated to establish stability or rapid deterioration.

# Caveats of eGFR
- eGFR is an estimated value that assumes a steady state of creatinine generation. o eGFR may be unreliable in extremes of muscle mass or with certain diets (e.g., very high or very low protein). Some medications can interfere with the excretion of creatinine (e.g., trimethoprim, fenofibrate). 14,15 o In hospitalized patients or patients with AKI the fluctuations in creatinine make eGFR unreliable. In these circumstances, creatinine values should be used to guide management. o As a general rule, the eGFR can be used as a guide to outpatient drug dosing, even if the references use creatinine clearance (eCrCl). More caution is required for drugs with significant potential toxicity or a narrow therapeutic window (e.g., chemotherapy).

# Urinalysis and ACR Values and Interpretation
- Significant abnormalities include persistent white blood cells or red blood cells in the absence of infection or instrumentation, and the presence of cellular casts. - Urine ACR (uACR) is the preferred method to screen for protein in the urine.
- uACR quantifies albuminuria in a range which is not detected by dipstick urinalysis. o The term microalbumin has historically been used. Recent guidelines and consensus from laboratories have recommended abandoning this term and to quote the uACR value instead. 13 o uACR elevation (>3.0 mg/mmol) on serial testing is abnormal. o In patients without diabetes, no specific treatment is recommended for isolated uACR values between 3 and 30 mg/mmol. These individuals remain at risk of CKD progression and cardiovascular disease, therefore surveillance is warranted. o uACR may be unreliable in some patients due to acute illness, vigorous exercise, poorly controlled hypertension or poorly controlled blood glucose. Repeat testing should be done when in doubt.
- Urine test abnormalities, even with persistent eGFR values  60 mL /min per 1.73m 2 suggest kidney disease.
- 24-hour urine collections are not necessary in most cases.
- For equivalence of dipstick protein measurements, uACR and protein/creatinine ratios (PCR), see Appendix.

# Renal Imaging
- Renal ultrasound should be undertaken to assess structural abnormalities and aid in diagnosis. Renal ultrasound should be performed in the following cases: o Obstructive urinary symptoms o Unexplained microscopic or macroscopic hematuria o Unclear etiology of CKD, especially in young patients o Patients with suspicion of benign prostatic hypertrophy (BPH) o Family history of structural renal disease (e.g., cystic kidney disease)
Staging of CKD Risk staging of kidney disease is important for care planning and patient management. Risk is determined based on Cause, eGFR, and uACR, or CGA. Refer to Figure 1 (page 1). Further details on risk determination are available on the Kidney Disease Improving Global Outcomes (KDIGO) CKD management guideline at kdigo.org/home/guidelines. 13 

# Risk Calculators
The Kidney Failure Risk Equation (KFRE) is an equation designed to estimate probability of requiring dialysis within 2 or 5 years. The equation is derived from 4 variables and can be calculated using QxMD: qxmd.com. Risks of > 10 -20% indicate high risk (analogous to Framingham risk scores). The KFRE is a useful tool for prognostication, however its role has yet to be established in routine clinical practice.

# Referral Recommendations
Indications for referral to specialist/nephrologist 22  Very high risk kidney disease (urgent communication needed)
- Presence of active urine sediments (red blood cell casts or cellular casts  protein), especially when associated with reduced eGFR. - AKI in absence of readily reversible cause (e.g., volume depletion, NSAIDs) - Abrupt sustained fall in eGFR in a patient with known CKD.

# - eGFR < 15 - Nephrotic syndrome

# High risk kidney disease (patient to be seen within a timely fashion)
- GFR 30 mg/mmol (regardless of eGFR) e.g., in absence of diabetes or HTN - Progressive CKD, with eGFR decline > 5 ml/min/year  - Diabetes and evidence of CKD with eGFR 30
Low to moderate risk kidney disease (patients that could be seen within a longer time interval, e.g., within 6 mos)
- Persistent abnormalities of serum potassium.
- Hereditary kidney disease.
- CKD, eGFR 30-45 - CKD and difficult to treat hypertension  Time to first consultation will vary based on individual circumstances. Discussion with your local nephrologist as to timing of referral for specific individuals is encouraged if in doubt.

# Recommended history and tests to include in referral package:
- A urology consult is more appropriate than nephrology in the following scenarios:
- Renal mass, enlarged prostate, obstruction, and large symptomatic or obstructing kidney stone

# Management
Refer to Figure 1 (page 1) for recommended follow-up intervals.

# Customization of management plan
- Many patients with CKD have multiple comorbidities. In some situations, universal fixed targets may not be applicable and may even be harmful. Clinical judgment and individualized targets are recommended. - Communication with specialists is encouraged if appropriateness of any of the targets is in question. 

# Kidney function measurements
- Refer to Figure 1 for frequency of eGFR and uACR measurements in specific risk categories.
- Repeat eGFR sooner (within 10 days) after any change in medications (e.g., ACEi, ARB, or diuretics, SGLT2i), medical intervention, or hospitalization. - Check creatinine and potassium prior to starting ACEi, ARB, SGLT2i, MRA within 7-14 days of starting, and within 7-14 days after a dose increase. - Creatinine rise >20% after dose increase should be followed by further measurements within 7-14 days.
Blood pressure 

# Vaccinations
- Influenza vaccine annually.
- Pneumococcal and Hepatitis B vaccines recommended for adults at medically high risk.
- Refer to immunizebc.ca for other recommended vaccines by age and risk profile
Patients with very advanced CKD are less likely to seroconvert after hepatitis B immunization. Confirmation of immunity is required after vaccination, which may need to be repeated (after consultation with specialist)

# Lifestyle and Self-Management
Support patient self management with the means available in your community. Patients with CKD benefit from multidisciplinary renal teams who can support patients to make beneficial changes in diet, smoking and physical activity, and to understand medications, and the uncertainty and emotional distress that can be seen in those with chronic conditions. Denial, often associated with grief, is common in patients with chronic disease affecting a vital organ.
Encourage patients with CKD to consider advance care planning and their goals for future care, including for the end of life. o Provincial advance care planning resources are available at gov.bc.ca/advancecare o BC Guidelines on palliative care are available at bcguidelines.ca/submenu_palliative.html o BC Renal Agency information about end of life care is available at bcrenalagency.ca/healthcare-professionals/end-liferesources

# Complex Scenarios
The following common complex scenarios benefit from discussion with a specialist:
- Whether to change the approach to a patient when eGFR goes down to 30  - Pathways -PathwaysBC.ca An online resource that allows GPs and nurse practitioners and their office staff to quickly access current and accurate referral information, including wait times and areas of expertise, for specialists and specialty clinics. In addition, Pathways makes available hundreds of patient and provider resources that are categorized and searchable.
- HealthLink BC: healthlinkbc.ca HealthLink BC provides reliable non-emergency health information and advice to patients in BC. Information and advice on managing chronic kidney disease in several languages is available by telephone, website, a mobile app and a collection of print resources. Patients can speak to a health services navigator, registered dietitian, registered nurse, qualified exercise professional, or a pharmacist.
Patients may call 8-1-1 toll-free in B.C., or for the deaf and the hard of hearing, call 7-1-1.
- Health Data Coalition: hdcbc.ca An online, physician-led data sharing platform that can assist you in assessing your own practice in areas such as chronic disease management or medication prescribing. HDC data can graphically represent patients in your practice with chronic kidney disease in a clear and simple fashion, allowing for reflection on practice and tracking improvements over time.
The principles of the Guidelines and Protocols Advisory Committee are to:
- encourage appropriate responses to common medical situations - recommend actions that are sufficient and efficient, neither excessive nor deficient - permit exceptions when justified by clinical circumstances

# Contact Information:
Guidelines and Protocols Advisory Committee PO Box 9642 STN PROV GOVT Victoria BC V8W 9P1 Email: hlth.guidelines@gov.bc.ca Website: www.BCGuidelines.ca