Chronic kidney disease (CKD) and periodontitis share a bidirectional inflammatory relationship, with cytokines such as IL-6, TNF-α, and hsCRP driving progression in both conditions. Non-surgical periodontal therapy (NSPT) has shown reductions in systemic inflammatory markers with emerging evidence of improved renal function, yet robust randomized controlled trials targeting pre-dialysis stage IV-V diabetic CKD patients remain lacking. In the Indian context, where diabetes-related CKD is rapidly rising and access to dialysis is limited, there is a clear lacuna in literature regarding the effectiveness of NSPT in delaying progression to end-stage renal disease. Hence, the present non-randomized clinical study is undertaken to address this gap.

Chronic kidney disease (CKD) is a major socio-economic and healthcare problem and represents a significant global public health challenge. The burden of disease is disproportionately higher in low- and middle-income countries. As per the Global Burden of Disease (GBD) 2023 estimates, approximately 788 million people were affected by CKD globally, with a global age-adjusted prevalence of 14.2% among adults aged 20 years and older. CKD has a significant global burden, affecting over 9% of the world population and was directly responsible for 1.2 million deaths worldwide in 2017 alone.

Chronic kidney disease is defined as the presence of kidney damage or an estimated glomerular filtration rate (eGFR) of less than 60 ml/min/1.73 m² persisting for three months or more, irrespective of the underlying cause. It represents a state of progressive loss of kidney function, ultimately resulting in the need for renal replacement therapy in the form of dialysis or kidney transplantation. Kidney damage refers to pathological abnormalities detected by imaging or renal biopsy, abnormalities in urinary sediment, or increased urinary albumin excretion rates.

The leading cause of CKD is diabetes mellitus, followed by hypertension and glomerular diseases. The prevalence of individuals with CKD due to type 1 diabetes has continued to increase globally, rising by 21.7% between 2007 and 2017 and reaching approximately 3.2 million individuals in 2017. These individuals are at increased risk of cardiovascular complications, and nearly 25-30% progress to kidney failure. Irrespective of the initial nephropathy, once a critical mass of nephrons is lost, kidney disease generally follows a progressive course toward advanced stages, resulting in increased morbidity and mortality.

The burden of CKD arises not only from the management of end-stage renal disease but also from complications related to CKD and its associated comorbidities. There are effective strategies to reduce the rate of CKD progression and improve patient outcomes; therefore, the need for therapies aimed at slowing disease progression is critical.

Periodontal bacteria, which cause chronic inflammation and the breakdown of tooth-supporting structures, are the cause of periodontal disease, a chronic infectious oral illness. One of the most prevalent oral illnesses worldwide is periodontitis, affecting almost 20-50% of the global population in varying degrees, and the percentage rises with advancing age. In India, 51% of people had periodontal disease overall. Periodontal disease is implicated as an independent risk factor for CKD. Periodontitis is defined as an inflammatory disease of the supporting tissues of the teeth caused by specific microorganisms or groups of microorganisms, resulting in progressive destruction of the periodontal ligament and alveolar bone, with periodontal pocket formation, gingival recession, or both.

Chronic kidney disease and periodontal disease are strongly interconnected through shared inflammatory, metabolic, and immune pathways. Periodontal disease has been implicated as an independent risk factor for CKD and may also act as a risk factor for several acquired systemic diseases. The bidirectional relationship between periodontal disease and systemic conditions highlights the importance of oral health assessment in medically compromised populations.

Inflammation is defined as the tissue's biological response to harmful stimuli such as pathogens or irritants. Chronic inflammation and elevated inflammatory markers play a crucial role in the progression and adverse outcomes of CKD. Evidence from previous studies demonstrates that declining renal function is associated with increased levels of circulating inflammatory cytokines. Several investigations have proposed that chronic dental infections, particularly periodontal disease, contribute significantly to the systemic inflammatory burden observed in CKD patients. The pathophysiological concept of periodontitis involves the systemic dissemination of inflammatory mediators such as CRP, IL-6, and tumor necrosis factor-α (TNF-α), either due to local bacterial infection causing periodontal tissue destruction or through the systemic spread of periodontal pathogens and their endotoxins. Periodontitis, being a chronic inflammatory condition, may significantly amplify the existing systemic inflammatory burden in CKD, thereby contributing to disease progression and associated complications.

Periodontal infections worsen the systemic inflammatory status, leading to poor renal outcomes in CKD patients. Improving oral health care through non-surgical periodontal therapy may improve the systemic inflammatory status and renal function. Various studies demonstrated elevated levels of CRP and IL-6 in patients with periodontal disease and their significant reduction following non-surgical periodontal therapy (NSPT). These findings suggest that periodontal intervention may play a role in modulating systemic inflammation.

In the Indian context, where the prevalence of diabetes and CKD is increasing rapidly and access to dialysis remains limited for a large proportion of the population, strategies aimed at delaying progression to end-stage renal disease are of particular importance. Oral health is often neglected in medically compromised individuals, and periodontal disease frequently remains untreated. Addressing periodontal health may therefore represent an overlooked yet impactful component of comprehensive CKD care.

Thus, the present non-randomized controlled study is designed to evaluate the effectiveness of subgingival instrumentation in delaying the progression to end-stage renal disease or the initiation of dialysis among diabetic patients with stage IV chronic kidney disease. By assessing both periodontal and renal parameters over a defined follow-up period of 12 months, this study aims to generate evidence supporting the integration of periodontal care into the comprehensive management of diabetic CKD patients.

Inclusion Criteria:

• Patients aged 40-70 years.
• Type 2 diabetes mellitus with chronic kidney disease and currently on oral hypoglycaemic agents.
• Diagnosed with Stage IV or V (eGFR between 15-20 mL/min/1.73m²).
• Not undergoing dialysis.
• Presence of ≥20 natural teeth.
• Diagnosed with moderate (Stage II) (as per 2017 World Workshop classification) (Interdental CAL at site of greatest loss >2mm but <5 mm in ≥ 2 non-adjacent teeth).
• Willingness to provide written informed consent.

Exclusion Criteria:

• Patients already undergoing haemodialysis or renal transplantation.
• Patients on insulin therapy or taking SGLT2 inhibitors and GLP-1 receptor agonists.
• HbA1c level >8 %.
• Any Periodontal therapy within past 6 months.
• Immunocompromised patients.
• Any history of tobacco use.
• Pregnant or lactating women.