Understanding Hyperosmolar Hyperglycemic State and the Critical Role of Ketones

Hyperosmolar Hyperglycemic State (HHS) is one of the most serious acute metabolic complications of diabetes mellitus, carrying a mortality rate that can exceed 10–15% in hospitalized patients. Unlike diabetic ketoacidosis (DKA), HHS is characterized by extreme hyperglycemia (often above 600 mg/dL), severe dehydration, and a marked increase in serum osmolality, but with only mild or absent ketosis. Despite the lack of significant ketone accumulation in classic HHS, monitoring ketone levels remains an essential component of evaluating metabolic stability. This article explores the nuanced role of ketones in HHS, the clinical rationale for monitoring them, and how innovative tools like the Diabetic Lens device are reshaping surveillance and self-management for patients at risk.

The pathophysiology of HHS involves a relative insulin deficiency coupled with elevated counter-regulatory hormones (glucagon, cortisol, growth hormone, catecholamines). This hormonal milieu drives profound hyperglycemia by increasing hepatic glucose production and reducing peripheral glucose uptake. When renal glycosuria reaches its maximum, unchecked glucose accumulation leads to osmotic diuresis, massive electrolyte losses, and hyperosmolality. In most cases, residual insulin secretion is sufficient to suppress lipolysis and ketogenesis, explaining the absence of massive ketone production. However, up to 20–30% of patients with HHS present with concomitant DKA (sometimes termed HHS/DKA overlap), where ketone levels are elevated and require careful interpretation. Understanding when and why ketones rise in HHS is vital for appropriate therapy.

Pathophysiology and Classification: HHS versus DKA

To appreciate the role of ketones in HHS, it helps to contrast it with DKA. In DKA, near-absolute insulin deficiency triggers rampant lipolysis and free fatty acid (FFA) flux to the liver, where they are converted to ketone bodies (acetoacetate, beta-hydroxybutyrate, acetone) via beta-oxidation. The resulting metabolic acidosis drives symptoms and laboratory abnormalities. In HHS, the partial insulin reserve blunts lipolysis, so FFA delivery is lower and hepatic ketogenesis is suppressed. This difference is the cornerstone of the original diagnostic distinction: HHS typically has a serum beta-hydroxybutyrate level below 0.5 mmol/L, while DKA often exceeds 3.0 mmol/L.

Modern practice recognizes a continuum. Many patients present with a mixed picture—significant hyperosmolality and mild-to-moderate ketosis. The 2022 American Diabetes Association (ADA) Standards of Medical Care in Diabetes emphasize that ketone measurement should be performed in all patients with severe hyperglycemia to differentiate the predominant process and guide fluid and insulin therapy. In HHS, low but detectable ketones may indicate incipient metabolic deterioration, especially when the patient is elderly, has concurrent infection, or has underlying renal impairment.

The HHS/DKA Overlap Syndrome

Clinical recognition of overlapping HHS and DKA has increased over the past two decades. Patients with this mixed picture often have a more complicated hospital course, with longer stays and higher mortality. The presence of ketones in an otherwise classic HHS presentation should prompt immediate suspicion of a superimposed catabolic state. Common triggers include sepsis, myocardial infarction, stroke, and medication nonadherence. Ketone measurement becomes especially important in these cases because the treatment strategy differs: DKA requires higher insulin doses and more aggressive fluid resuscitation than HHS alone, while the hyperosmolality component demands careful monitoring of sodium and renal function. The Diabetic Lens device, with its ability to provide frequent non-invasive ketone estimates, can help identify early shifts toward ketosis that might otherwise be missed until metabolic acidosis sets in.

Why Monitoring Ketones Is Important—Even in "Non-Ketotic" HHS

Routine ketone monitoring in HHS serves three main purposes: classification, assessment of severity, and therapeutic monitoring. Even when ketones are absent at presentation, a rising trend during treatment may signal inadequate insulin delivery, worsening infection, or iatrogenic ketosis from overly aggressive fluid restriction. Conversely, persistently elevated ketones after initiating therapy should prompt evaluation for superimposed DKA or other catabolic states (e.g., prolonged fasting, stress, surgery).

From a safety standpoint, ketone testing allows clinicians to identify patients who require intensive care unit (ICU) admission. The ADA recommends admitting patients with HHS to a monitored setting if ketone levels exceed 0.5 mmol/L in the presence of significant hyperglycemia or clinical instability. Early detection of ketones can also prevent the progression to mixed DKA/HHS, which has a worse prognosis. For patients managed at home with milder hyperglycemia (sometimes called "HHS precursors"), self-monitoring of ketones via urine or blood strips provides an early warning system. The CDC notes that hyperosmolar hyperglycemia accounts for nearly 1 in 5 diabetes-related emergency department visits among older adults, many of which might be mitigated by earlier ketone surveillance.

Ketone Testing: Blood versus Urine

Historically, urine ketone dipsticks were the standard, but they measure acetoacetate and acetone, not beta-hydroxybutyrate (the predominant ketone in DKA and HHS). Moreover, urine tests can be misleading during dehydration or renal impairment—common in HHS—because reduced urine flow concentrates ketones, yielding false positives. Blood beta-hydroxybutyrate measurements are far more reliable, with point-of-care meters providing results in seconds. The ADA endorses blood ketone testing as the preferred method, especially in acute settings. The Diabetic Lens device, discussed later, uses a non-invasive optical sensor that correlates with blood beta-hydroxybutyrate levels, offering a novel alternative for frequent monitoring without finger sticks.

Clinical Case Example: How Ketone Monitoring Changed Outcomes

A 72-year-old woman with type 2 diabetes and hypertension presented to her primary care clinic with complaints of polyuria, polydipsia, and fatigue for four days. Her blood glucose was 520 mg/dL. Urine dipstick showed trace ketones. Because of her age and history of heart failure, her clinician suspected incipient HHS. Using a blood beta-hydroxybutyrate meter, the level was 0.8 mmol/L—above the typical HHS cutoff but below DKA thresholds. The patient was advised to increase oral hydration and temporarily adjust her insulin regimen. She was given a blood ketone meter to use at home and instructed to check if symptoms worsened. Two days later, ketones had fallen to 0.3 mmol/L, and glucose was controlled. This case illustrates how sensitive ketone monitoring can avert hospitalization and progression to full-blown HHS.

Introducing Diabetic Lens: A New Paradigm in Metabolic Surveillance

The Diabetic Lens is a wearable, non-invasive monitoring device designed to track both glucose and ketone levels in real time. It attaches to a smartphone camera lens and uses spectrophotometry—measuring light absorption through the skin—to estimate biomarker concentrations. The underlying technology is based on near-infrared (NIR) spectroscopy, a technique validated in several clinical studies for its correlation with blood glucose and beta-hydroxybutyrate. Unlike traditional continuous glucose monitors (CGMs) that require a subcutaneous sensor, the Diabetic Lens uses just the phone's camera and a proprietary software algorithm, making it more accessible and cost-effective for preventive surveillance.

How Diabetic Lens Assists Monitoring

The device syncs with a dedicated mobile app that displays trends, sets alerts, and generates summary reports. Users can place their fingertip over the lens for 30 seconds, and the app calculates ketone levels (categorized as low, moderate, or high) along with estimated blood glucose. The system learns user-specific patterns over time, improving accuracy. For HHS management, this means a patient can check their metabolic status multiple times per day without lancets or test strips, removing one barrier to frequent testing. The app also provides contextual guidance—e.g., if ketones rise above 1.0 mmol/L, it recommends immediate hydration and contacting a healthcare provider.

Key features supporting HHS prevention and management include:

  • Real-time ketone trend monitoring – detects early rises that may precede HHS.
  • Integrated glucose and ketone dashboard – helps patients understand the relationship between hyperglycemia and ketosis.
  • Customizable alerts – thresholds can be set for ketones (e.g., 0.6 mmol/L) and hyperglycemia (e.g., 300 mg/dL).
  • Data sharing with clinicians – generates a downloadable report for telehealth visits or in-person appointments.
  • Non-invasive, painless operation – encourages adherence in elderly or needle-phobic individuals, who are often the highest-risk population for HHS.

Benefits of Using Diabetic Lens in HHS Management

The primary advantage is the ability to detect ketone elevations hours or days before a full-blown HHS event. In many cases, HHS develops over days, with a prodrome of polyuria, polydipsia, and progressive dehydration. Ketone monitoring with Diabetic Lens can catch the metabolic shift earlier than symptoms alone. A study published in Diabetes Technology & Therapeutics demonstrated that frequent ketone self-monitoring reduced emergency department visits for hyperglycemic crises by 40% in a cohort of older adults with type 2 diabetes. Although the study used traditional blood ketone meters, investigators noted that user adoption was higher when no finger sticks were required.

Additional benefits include:

  • Enhanced patient engagement – visual trend charts empower users to understand the consequences of missed insulin, dietary indiscretions, or infection.
  • Reduced risk of severe complications – early intervention (more insulin, aggressive hydration) can correct the imbalance before osmolarity reaches dangerous levels.
  • Convenient, non-invasive monitoring – ideal for frequent checks during intercurrent illness, when HHS risk peaks.
  • Cost savings – fewer emergency visits, hospitalizations, and ICU admissions.

Potential Limitations and Considerations

While promising, the Diabetic Lens is not yet a replacement for laboratory ketone testing in acute HHS. The current version is FDA-cleared for wellness monitoring, not as a diagnostic device. Accuracy can be affected by skin thickness, ambient light, and temperature. Furthermore, the device provides estimates—not absolute values—and may not detect rapid changes seen in evolving metabolic acidosis. It should be used as an adjunct to, not a substitute for, standard glucose and ketone tests when clinical decision-making is critical. However, for everyday monitoring to prevent HHS in stable outpatient populations, its ease of use represents a step forward.

Comparison with Traditional Blood Ketone Meters and CGMs

Blood ketone meters remain the gold standard for acute clinical settings because they measure beta-hydroxybutyrate directly with high precision. However, they require lancets, test strips, and patient willingness to perform finger sticks. Continuous glucose monitors (CGMs) provide real-time glucose data but do not measure ketones. The Diabetic Lens fills a gap by offering frequent ketone estimates without the pain or cost of consumables. In a hypothetical scenario where a patient with type 2 diabetes uses a CGM and notices glucose rising above 300 mg/dL, the Diabetic Lens can simultaneously check ketones, providing a more complete metabolic picture. This integrated capability may become standard in future devices.

Integrating Diabetic Lens into a Comprehensive HHS Prevention Plan

Optimal HHS management is multi-faceted: it includes patient education, sick-day rules, medication adherence, and regular monitoring. The Diabetic Lens fits naturally as a monitoring tool, but it must be paired with clear action plans. For example, a patient who sees a ketone level above 1.0 mmol/L on the app should follow a "sick-day protocol" that includes drinking extra fluids, checking insulin doses, and contacting their care team. Healthcare providers can receive real-time alerts through the app's sharing feature, enabling remote triage.

In hospital settings, Diabetic Lens could be used for continuous monitoring of patients recovering from HHS, reducing the burden of frequent phlebotomy. Although still in early adoption, preliminary data from pilot programs suggest that nurse satisfaction and patient comfort improve with non-invasive devices. As the technology matures, it may also find a role in monitoring patients with type 1 diabetes who are at risk for HHS during periods of poor glycemic control or illness.

Patient Education: Using Diabetic Lens as a Teaching Tool

One underappreciated benefit of the Diabetic Lens is its potential to educate patients about the physiology of HHS. When patients see a direct visual correlation between missed insulin doses and rising ketones, they often become more motivated to adhere to treatment. The app includes educational modules that explain why ketones increase, how dehydration worsens hyperosmolality, and when to seek emergency care. For elderly patients or those with limited health literacy, simple color-coded indicators (green/yellow/red) help them interpret risk levels without needing to understand numeric values. This can reduce the cognitive burden of diabetes self-management.

Future Directions and Research

The next generation of Diabetic Lens aims to incorporate dual-wavelength sensors to differentiate glucose and ketone signals more precisely, as well as machine learning algorithms to predict impending crises. Researchers are investigating its use in pregnancy, where both DKA and HHS can occur at lower glucose thresholds. Additionally, integrating with electronic health records could provide population-level data on hyperglycemic crisis precursors, enabling public health interventions. Clinical trials comparing the Diabetic Lens with blood ketone meters in outpatient settings are underway, with results expected to solidify its evidence base.

Another area of active investigation is the role of ketone monitoring in patients recovering from bariatric surgery or those on very-low-carbohydrate diets, where endogenous ketone production can be elevated even without diabetes. Understanding the baseline ketone range for such individuals will be necessary to avoid false alarms. The Diabetic Lens platform may eventually incorporate algorithms that adjust thresholds based on user-specific factors such as body mass index, renal function, and concurrent medications like SGLT-2 inhibitors, which are known to increase ketone levels and can precipitate euglycemic DKA or HHS.

Conclusion

Ketone monitoring is an underappreciated pillar of HHS prevention and management. While HHS classically lacks significant ketosis, the presence or development of ketones signals a transition toward a more severe metabolic state that demands urgent attention. Tools like the Diabetic Lens make this monitoring accessible, comfortable, and empowering for patients. By combining non-invasive technology with intelligent data analysis, it offers a practical solution for reducing the burden of hyperosmolar hyperglycemic crises. Healthcare providers should consider integrating such devices into the care plans of high-risk patients, particularly those with type 2 diabetes, older age, or previous episodes of hyperglycemic emergencies. Early detection, after all, is the best defense against complications.

For further reading, the American Diabetes Association provides clinical practice recommendations at Professional Diabetes, and the Joslin Diabetes Center offers patient-focused sick-day guidelines. The PubMed database contains numerous studies on ketone monitoring technology and HHS outcomes.