Chronic kidney disease (CKD) is a condition where the kidneys gradually lose function over time. There are 5 stages of CKD, with stage 1 being the mildest and stage 5 being kidney failure requiring dialysis or transplantation. Patients are understandably concerned about disease progression and want to know how long it takes to go from one stage to the next. This article examines the time frame for progression from stage 1 to stage 2 CKD.
What is stage 1 CKD?
Stage 1 CKD is defined as kidney damage with normal or high kidney function. The glomerular filtration rate (GFR), a measure of kidney function, is 90 mL/min or above in stage 1. Kidney damage is marked by the presence of albuminuria, abnormal urine sediments, or abnormalities on imaging tests. Patients usually have no symptoms in stage 1 and it is often detected incidentally on lab tests or imaging done for other reasons.
Signs of stage 1 CKD
- GFR ≥90 mL/min
- Kidney damage on pathology, urine, or imaging tests
- No symptoms
What is stage 2 CKD?
Stage 2 CKD represents mild loss of kidney function. The GFR is 60-89 mL/min in this stage. As in stage 1, patients are typically asymptomatic and stage 2 is often discovered on routine blood and urine tests. Without treatment, stage 2 CKD tends to slowly get worse over time.
Signs of stage 2 CKD
- GFR 60-89 mL/min
- Kidney damage on pathology, urine, or imaging tests
- Usually no symptoms
How quickly does stage 1 progress to stage 2 CKD?
Unfortunately, there are no definitive timelines for progression from stage 1 to stage 2 CKD. The rate of progression varies substantially between individuals based on the underlying cause of kidney disease and presence of risk factors. However, some general time frames have been described in medical literature:
- In diabetic kidney disease, progression from stage 1 to stage 2 takes approximately 2-5 years on average.
- In hypertensive nephrosclerosis, progression takes around 5-10 years.
- In kidney disease due to autoimmune disorders like lupus, progression to stage 2 may occur over 5-15 years.
- In inherited kidney diseases like polycystic kidney disease, stage 2 develops 10 years or more after stage 1.
These time ranges represent averages—in any individual the progression may be faster or slower. Black race, older age, high blood pressure, diabetes, and proteinuria tend to accelerate progression to stage 2 CKD.
Factors affecting progression from stage 1 to stage 2 CKD
Many factors influence the rate of decline in kidney function from stage 1 to stage 2 CKD:
Cause of kidney disease
Certain kidney diseases intrinsically lead to faster deterioration of function. For example, progression is generally faster in diabetes and hypertension compared to polycystic kidney disease or IgA nephropathy.
Level of proteinuria
Proteinuria, or leakage of protein into the urine, signals ongoing kidney damage. More severe proteinuria accelerates progression to stage 2 CKD.
Blood pressure control
Uncontrolled high blood pressure leads to worsening of CKD. Effective blood pressure treatment slows progression from stage 1 to 2.
Glycemic control in diabetes
Poor control of blood sugars in diabetes promotes kidney function decline. Tight glycemic control helps delay progression to stage 2.
Other risk factors
Older age, African-American race, smoking, and obesity are also risk factors for faster progression of CKD from stage 1 to stage 2.
Here is a table summarizing the key factors that hasten or slow progression from stage 1 to stage 2 CKD:
| Factors accelerating progression | Factors slowing progression |
|---|---|
| Diabetes | Good blood pressure control |
| Hypertension | Good blood sugar control in diabetes |
| Heavy proteinuria | Low protein diet |
| African-American race | ACE inhibitors or ARBs |
| Older age | Smoking cessation |
| Obesity | Weight loss |
Preventing progression to stage 2 CKD
While the intrinsic nature of the kidney disease influences progression, there are many steps that can be taken to slow deterioration of kidney function and delay advancement to stage 2:
- Control blood pressure – Keeping blood pressure below 130/80 mm Hg reduces kidney damage.
- Control blood sugars – In diabetes, maintaining an HbA1c under 7% helps preserve kidney health.
- Block the RAAS – RAAS stands for renin-angiotensin-aldosterone system. ACE inhibitors and ARBs are medications that interrupt this system and slow CKD progression.
- Reduce proteinuria – Lowering urinary protein excretion helps slow functional decline of the kidneys.
- Healthy lifestyle – Quit smoking, lose weight, exercise, and eat a kidney-friendly diet.
Adhering to medication and lifestyle recommendations tailored to the individual’s needs optimizes kidney outcomes and delays advancement to stage 2 CKD.
How is stage 2 CKD treated?
There are no specific medications to treat stage 2 CKD per se. Management focuses on slowing disease progression and reducing risk of complications. Key aspects include:
- Lowering blood pressure – Many patients require 2 or more BP medications to achieve goals.
- Controlling blood sugar – Close monitoring and multiple diabetes meds are often needed.
- Blocking RAAS – ACEi or ARB even if normotensive.
- Restricting protein – Reducing dietary protein to 0.8-1 g/kg/day.
- Restricting sodium – Keeping sodium intake <2.4 g/day.
- Smoking cessation – Eliminating tobacco use.
- Nutrition – Consulting with a renal dietician.
The cornerstones of treatment are controlling blood pressure, reducing proteinuria, and adopting an overall kidney healthy lifestyle. Maintaining good metabolic and vascular health also helps delay progression.
Medications used in stage 2 CKD
Examples of medications used to treat stage 2 CKD and delay worsening include:
- ACE inhibitors like lisinopril or ARBs like losartan to lower blood pressure and reduce proteinuria
- Calcium channel blockers like amlodipine to control blood pressure
- Diuretics like furosemide or HCTZ as needed for fluid retention
- Sodium-glucose cotransporter-2 (SGLT2) inhibitors like empagliflozin benefit diabetic kidney disease
- Anti-platelets like aspirin to reduce cardiovascular risk
- Statins like atorvastatin to lower cholesterol and risk
- Erythropoiesis-stimulating agents (ESAs) if anemic
- Iron supplements if iron deficient
- Sodium bicarbonate or sevelamer if acidotic
Monitoring progression of stage 2 CKD
Patients with stage 2 CKD require regular monitoring to assess disease progression and response to therapy. Recommended follow-up includes:
- Office visits at least every 6 months
- Blood pressure checks at every visit
- Urinalysis and urine protein at every visit
- Serum creatinine and eGFR every 6-12 months
- Serum electrolytes every 6-12 months
- Glycemic monitoring in diabetes
More frequent testing may be appropriate for those at high risk of progression or with extensive treatment adjustments. Trends in eGFR and proteinuria are particularly important.
Goals of monitoring in stage 2 CKD
- Assess response to therapy
- Identify progression to stage 3
- Adjust medications to improve BP and proteinuria
- Identify and address complications
- Provide patient education
Vigilant monitoring allows optimization of care to delay advancement to stage 3 disease.
Prognosis of stage 2 CKD
The prognosis for stage 2 CKD primarily depends on how rapidly kidney function deteriorates. Those who remain stable with treatment can live many years without developing advanced CKD. However, patients with uncontrolled risk factors progress more quickly. Development of stage 3 CKD signals worsening prognosis.
Outcomes of stage 2 CKD
- Low risk of kidney failure in the short term
- 5-year risk of kidney failure ~1%
- May stabilize with treatment
- May gradually progress to stage 3 and beyond
- Increased cardiovascular risk
Progression can be delayed through meticulous treatment, but stage 2 CKD should not be taken lightly given its implications for future health.
When to see a nephrologist in stage 2 CKD?
Most patients with stage 2 CKD can initially be cared for by their primary care physician. However, referral to a nephrologist is recommended in certain scenarios:
- Unclear etiology of CKD
- Rapid decline in GFR
- Unable to control BP or proteinuria
- Recurrent kidney stones or infections
- Advanced CKD complications
- Considering kidney transplant
Seeing a nephrologist early allows specific treatment to slow progression and reduce complications. A nephrology care plan can be initiated in stage 2 for high risk patients.
Benefits of seeing a nephrologist in stage 2 CKD
- Expert guidance on blood pressure management
- Minimizing risk of kidney failure
- Preserving kidney function long-term
- Reducing proteinuria
- Treating anemia, mineral disorders, fluid overload
- Planning for kidney failure if it occurs
The specialized knowledge of nephrologists helps optimize care of patients with stage 2 CKD.
Conclusion
Progression from stage 1 to stage 2 CKD is highly variable, as it may take anywhere from 2 to 20 years depending on the specific kidney disease and risk factor control. Careful treatment can maintain stability of stage 2 CKD for many years in some patients. However, close monitoring is crucial to identify worsening of kidney function before it advances too far. Prevention of diabetic and hypertensive kidney disease is also key to averting stage 2 CKD. Patient education, lifestyle changes, medication optimization, and specialist referral when appropriate allows the best outcomes in stage 2 CKD.