The video version of this podcast can be found here:

·      https://youtu.be/iJKpE3H_Lbk

This episode makes reference to guidelines produced by the "National Institute for Health and Care Excellence" in the UK, also referred to as "NICE". The content on this channel reflects my professional interpretation/summary of the guidance and I am in no way affiliated with, employed by or funded/sponsored by NICE.

NICE stands for "National Institute for Health and Care Excellence" and is an independent organization within the UK healthcare system that produces evidence-based guidelines and recommendations to help healthcare professionals deliver the best possible care to patients, particularly within the NHS (National Health Service) by assessing new health technologies and treatments and determining their cost-effectiveness; essentially guiding best practices for patient care across the country.

My name is Fernando Florido and I am a General Practitioner in the United Kingdom. In this episode I go through the guideline on CKD, NG203, by the National Institute for Health and Care Excellence (NICE), last updated in November 2021, focusing on what is relevant to Primary Care only.

Given how extensive the guidance is, in this episode I will just focus on diagnosis, and classification of CKD.

In the next two episodes, I will cover investigations, monitoring, referral recommendation and CKD management in Primary care.

I am not giving medical advice; this video is intended for health care professionals, it is only my summary and my interpretation of the guidelines and you must use your clinical judgement.  

Disclaimer:

The Video Content on this channel is for educational purposes and not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen on this YouTube channel. The statements made throughout this video are not to be used or relied on to diagnose, treat, cure or prevent health conditions.

In addition, transmission of this Content is not intended to create, and receipt by you does not constitute, a physician-patient relationship with Dr Fernando Florido, his employees, agents, independent contractors, or anyone acting on behalf of Dr Fernando Florido.

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There is a podcast version of this and other videos that you can access here:

Primary Care guidelines podcast:

·      Redcircle: https://redcircle.com/shows/primary-care-guidelines

·      Spotify: https://open.spotify.com/show/5BmqS0Ol16oQ7Kr1WYzupK

·      Apple podcasts: https://podcasts.apple.com/gb/podcast/primary-care-guidelines/id1608821148

There is a YouTube version of this and other videos that you can access here: 

• The Practical GP YouTube Channel: 

https://youtube.com/@practicalgp?si=ecJGF5QCuMLQ6hrk

The Full NICE guideline chronic kidney disease: assessment and management [NG203] can be found here:

·      https://www.nice.org.uk/guidance/ng203

The links to other relevant guidance covered in this episode can be found here:

The link to the non-visible haematuria video is:

·      https://youtu.be/SaizjWg7Fng?si=McvEYQO9O3chElkj

Transcript

If you are listening to this podcast on YouTube, for a better experience, switch to the video version. The link is in the top right corner of the video and in the episode description.

Hello and welcome, I am Fernando, a GP in the UK. Today, we are doing a review of the NICE guideline on CKD, or NG203, focusing what is relevant to Primary Care only.

Given how extensive the guidance is, in this episode I will just focus on diagnosis, and classification of CKD.

In the next two episodes, I will cover investigations, monitoring, referral recommendation and CKD management in Primary care, so stay tuned for those.

Right, let’s jump into it.

For this review, I have excluded recommendations related to children and young people with CKD. While their management is often similar to that of adults, most children with CKD are managed by secondary care and this is why I am focusing on adults

Let’s review the investigations recommended in CKD. CKD can be classified depending on the levels of renal function and the presence and degree of proteinuria.

So, let’s have a look at renal function first.

To assess kidney function, path labs should report a creatinine-based estimate of glomerular filtration rate, or eGFRcreatinine, alongside the serum creatinine result. For simplicity, from now on, I’ll refer to eGFRcreatinine simply as eGFR.

Because of how eGFR is calculated, eGFR results may be less reliable in certain situations when we should interpret it with caution. Examples are:

·      AKI because of the acute fluctuations in eGFR,

·      in oedematous states, where eGFR could be both over or underestimated depending on the case

·      pregnancy because it is associated with a physiologically increased kidney filtration rate,

·      muscle wasting disorders, amputation and in malnourishment because reduced muscle mass can lead to an overestimated higher eGFR, and

·      those who have higher muscle mass or use protein supplements because, conversely, they can have an underestimated lower eGFR. It is also for this reason, that we should also advise patients not to eat any meat in the 12 hours before having the blood test.

Although eGFR has not been well validated in certain ethnic groups like black, Asian and other minority ethnic groups in the UK, NICE has removed a previous recommendation of adjusting eGFR for specific ethnicities.

Also, because of lack of evidence, NICE no longer recommends measuring eGFRcystatin-c.

Path labs will report eGFR either as 'greater than 90 ml/min/1.73 m2' or as a whole number if it is 90 ml/min/1.73 m2 or less.

If renal function is suspected to be impaired despite an eGFR greater than 90 ml/min/1.73 m², a significant reduction in kidney function can be inferred if serum creatinine increases by more than 20%.

We also need to remember that eGFR becomes less accurate as the true GFR increases so we should interpret eGFR values of 60 ml/min/1.73 m2 or more with caution

If we have an eGFR less than 60 in someone not previously tested, we will confirm it by repeating the test within 2 weeks.

When interpreting changes in eGFR, we will allow for a natural variability of ±5% in serum creatinine levels. This range reflects both the biological fluctuations and the variability of the test in practice.

Let’s now look at investigations for proteinuria.

For the initial detection of proteinuria:

·      We will not use reagent strips unless they are capable of specifically measuring albumin at low concentrations and expressing the result as an albumin:creatinine ratio (or ACR). 

• If sending the urine to the path lab, we will request urine ACR rather than protein:creatinine ratio (or PCR) because of the greater sensitivity for low levels of proteinuria and
• If the ACR is between 3 mg/mmol and 70 mg/mmol, we will confirm it in a subsequent early morning sample. This is because the concentration of protein in the urine can fluctuate throughout the day due to physical activity, posture, and hydration, which makes early morning samples a more consistent and reliable measure. However, a repeat sample is not needed if the initial ACR is 70 mg/mmol or more. 

We will regard a confirmed ACR of 3 mg/mmol or more as clinically important proteinuria. 

Should we routinely screen for ACR?

Well, we should check urine ACR in the following groups:

• diabetes (either type 1 or type 2)
• eGFR of less than 60 
• eGFR of 60 more if there is a strong suspicion of CKD and
• children and young people with creatinine above the upper limit of normal.

When ACR is 70 mg/mmol or more, PCR can be used as an alternative to ACR. 

Earlier, we mentioned that reagent strips should not be routinely used to test for proteinuria. However, they are routinely used in practice. So, what should we do if we detect proteinuria or non-visible haematuria on the strip? Let’s have a look at these scenarios:

If unexplained proteinuria is an incidental finding on a reagent strip, we will offer testing for CKD using eGFR and ACR. 

Unlike proteinuria, for haematuria we should use reagent strips and we will investigate further for results of 1+ or higher. But we are specifically advised not to use urine microscopy to confirm a positive result as urine microscopy would not detect haemolysed haematuria. 

How do we manage isolated invisible haematuria?

If you haven’t already, I recommend checking the episode on non-visible haematuria on this channel. The link to it is in the episode description. But, in summary, to differentiate persistent non-visible haematuria without proteinuria from transient haematuria, two positive results out of three reagent strip tests are considered confirmation of persistent invisible haematuria.

Persistent invisible haematuria, with or without proteinuria, should prompt investigation for urinary tract malignancy in appropriate age groups.

For persistent non-visible haematuria without proteinuria, annual follow-up is recommended with repeat testing for haematuria, proteinuria, GFR, and blood pressure monitoring as long as the haematuria persists.

Who should be tested for CKD?

We will check eGFR and ACR if there is:

• diabetes
• hypertension
• previous episode of acute kidney injury
• cardiovascular disease
• structural renal tract disease, recurrent renal calculi or prostatic hypertrophy
• multisystem diseases with potential kidney involvement, for example, SLE
• gout
• family history of end-stage renal disease or hereditary kidney disease and
• incidental detection of haematuria or proteinuria. 

Additionally, we will monitor eGFR at least annually in people on medicines that can affect kidney function, for example lithium or long-term chronic use of NSAIDs.

Also, we should monitor people for CKD for at least 3 years after acute kidney injury (or longer for people with acute kidney injury stage 3) even if eGFR has returned to normal.

Once CKD has been detected, we will need to classify it using a combination of GFR and ACR categories.

The ACR categories are A1, A2 and A3 where:

·      A1: is when the ACR less than 3 mg/mmol

·      A2: is when the ACR 3 to 30 mg/mmol and

·      A3: is when the ACR over 30 mg/mmol

The GFR categories are G1 to G5 where:

·      G1: is when the eGFR 90 or over

·      G2: is when the eGFR 60 to 89

·      G3a: is when the eGFR 45 to 59

·      G3b: is when the eGFR 30 to 44

·      G4: is when the eGFR 15 to 29

·      G5: is when the eGFR under 15

Being aware that an increased ACR and decreased eGFR is associated with increased risk of adverse outcomes and that an increased ACR and decreased GFR in combination multiply this risk even further.

So that is it, a review of the diagnosis and classification of CKD.

We have come to the end of this episode. Remember that this is not medical advice but only my summary and my interpretation of the guidelines. You must always use your clinical judgement.

Thank you for listening and goodbye.