Actionable Intelligence
Every patient is a complex system — metabolic, inflammatory, sleep, renal, hepatic, cardiovascular, and nutritional systems interact continuously. Today's clinical tools analyze these in silos. Healthena's phenotyping engine connects them: we encode raw labs, vitals, and medications into discrete clinical states, align them to a common weekly timeline with confidence-weighted carry-forward, then run two parallel analyses — fuzzy clustering discovers overlapping health patterns, and lagged cross-correlation maps directional system-to-system influence. The outputs feed into calibrated risk predictors (XGBoost + Cox PH) targeting four longevity-relevant outcomes: cluster transition, new chronic diagnosis onset, cardiometabolic deterioration, and PhenoAge acceleration. Every component is non-generative and exportable.
The Problem
Healthcare today analyzes the human body in silos. A patient's metabolism, sleep, inflammation, kidney function, and biological aging are managed by different specialists, in different visits, looking at different metrics — but chronic disease doesn't respect silos. Sleep dysregulation affects glucose. Systemic inflammation affects recovery. Lipid dysfunction affects cognition. By the time a disease is diagnosed, multi-system damage has already accumulated for years.
Longevity and preventative-care clinics need to see the whole picture — but no clinical tool today integrates labs, vitals, medications, and trajectory into one cohesive view of how a patient is aging across all systems simultaneously. Existing tools either focus on single-disease risk (cardiovascular, diabetes) or produce dashboards of disconnected numbers without revealing the underlying phenotype.
Our Solution
The Multi-System Phenotyping Engine integrates labs, vitals, medications, and diagnoses across all physiological systems into discrete clinical states, aligns them on a common weekly timeline with confidence-weighted carry-forward, and uses fuzzy clustering to discover overlapping multi-system phenotypes directly from data — not from hand-named hypotheses.
The engine maps directional influence between systems (which systems predict which other systems' future states), assigns each patient a continuous membership vector across all discovered phenotypes, and predicts four longevity-relevant outcomes: phenotype transition from healthy to disease, new chronic diagnosis onset, cardiometabolic deterioration, and biological aging acceleration.
Every component is non-generative classical machine learning — fully exportable, auditable, and deployable in clinical settings.
Healthena Multi-System Phenotyping Engine
A non-generative classical ML pipeline for discovering and validating multi-system health phenotypes from longitudinal EHR data. Every output artifact is a learned parameter, threshold, or graph weight—never free-text generated by an LLM.
Pipeline Architecture
State Encoding converts raw clinical observations (labs, vitals, medications, diagnoses) into a discrete ternary representation ($-1$, $0$, $+1$) anchored to evidence-based clinical thresholds, enabling cross-metric comparison without scale harmonization.
Time Alignment projects heterogeneously-sampled observations onto a regular weekly grid using exponential confidence decay—the observed value is carried forward unchanged, but the system's confidence in that value decays with a modality-specific half-life, formally separating "what we know" from "how sure we are."
Parallel Analytic Branches extract two complementary structures: (a) Fuzzy C-Means clustering discovers overlapping multi-system health patterns; (b) Lagged cross-correlation maps directional influence between physiological systems. These converge into calibrated risk predictions (XGBoost + Cox PH) for four longevity-relevant outcomes.
1 State Encoding
The first transformation converts heterogeneous clinical observations into a discrete, comparable representation. Each metric is mapped to one of three states using its clinically established reference range as the decision boundary.
Threshold-Based Encoding
For metric $m$ with observed value $x$ at time $t$, and clinical thresholds lower bound $L_m$ and upper bound $U_m$:
$$s_t^m = \begin{cases} -1 & \text{if } x < L_m \quad \text{(below normal)} \\ \phantom{-}0 & \text{if } L_m \le x \le U_m \quad \text{(normal)} \\ +1 & \text{if } x > U_m \quad \text{(above normal)} \end{cases}$$For metrics without established clinical thresholds (e.g., HRV, sleep regularity), we fall back to cohort-percentile bucketing:
$$s_t^m = \begin{cases} -1 & \text{if } x \le P_{25}(\text{cohort}) \\ \phantom{-}0 & \text{if } P_{25} < x < P_{75} \\ +1 & \text{if } x \ge P_{75} \end{cases}$$The {−1, 0, +1} encoding looks like it loses information, but it doesn't. State encoding is purely a normalization tool for cross-modality comparability in the clustering step. The patient summary vector that flows into clustering and prediction retains all the continuous information:
- Carried numeric value with confidence weight (from Section 2)
- 1-month, 3-month, 12-month trajectory deltas (continuous)
- Volatility / standard deviation (continuous)
- Fraction of weeks in each state (continuous)
- Longest abnormal streak (continuous)
The discrete state is one feature among many. Downstream models see the rich continuous signal.
Encoding Demonstration
| Metric | Raw Value | Lower Threshold ($L_m$) | Upper Threshold ($U_m$) | State ($s_t^m$) | Interpretation |
|---|---|---|---|---|---|
| LDL Cholesterol | 150 mg/dL | — | 130 mg/dL | +1 | Above optimal |
| HbA1c | 6.3% | — | 5.7% | +1 | Pre-diabetic range |
| hsCRP | 1.5 mg/L | — | 3.0 mg/L | 0 | Normal range |
| eGFR | 85 mL/min | 60 mL/min | — | 0 | Normal renal function |
| Vitamin D | 16 ng/mL | 30 ng/mL | — | -1 | Deficient |
| Albumin | 4.2 g/dL | 3.5 g/dL | 5.5 g/dL | 0 | Normal range |
Sarah Chen, age 45, female. Eight key metrics encoded from her most recent lab panel:
| Metric | Raw Value | Threshold(s) | State |
|---|---|---|---|
| LDL | 150 mg/dL | U = 130 | +1 |
| ApoB | 120 mg/dL | U = 100 | +1 |
| HbA1c | 6.3% | U = 5.7 | +1 |
| Fasting Glucose | 122 mg/dL | U = 100 | +1 |
| hsCRP | 1.5 mg/L | U = 3.0 | 0 |
| eGFR | 85 mL/min | L = 60 | 0 |
| Vitamin D | 16 ng/mL | L = 30 | -1 |
| Albumin | 4.2 g/dL | L=3.5, U=5.5 | 0 |
State vector: $\mathbf{s}_{\text{Sarah}} = [+1, +1, +1, +1, 0, 0, -1, 0]$
Four of eight metrics are in the abnormal range, all concentrated in the metabolic domain (LDL, ApoB, A1c, glucose). This pattern will drive high membership in the Metabolic-Driven cluster in Section 3. The Vitamin D deficiency ($-1$) will contribute to the Nutritional-Deficient dimension. Notably, inflammatory (hsCRP) and renal (eGFR) markers are normal, which constrains the differential.
2 Time Alignment with Confidence Weighting
Carried Value
Let $t' < t$ be the most recent measurement time for metric $m$ before grid point $t$. The carried value is:
$$x_{\text{carried}}^m(t) = x_{t'}$$The value is unchanged—no interpolation, no extrapolation.
Confidence Decay
$$c_m(t, t') = \exp\!\left(-\frac{t - t'}{\tau_m}\right)$$where $\tau_m$ is the modality-specific half-life time constant.
Optional Shrinkage to Prior
$$x_{\text{aligned}}^m(t) = c \cdot x_{t'} + (1 - c) \cdot \mu_m$$Modality Half-Lives
| Modality | Decay constant (days) | Half-life (days) | Rationale |
|---|---|---|---|
| Wearable vitals (HR, HRV, SpO2) | 7 | 4.9 | High-frequency signal; physiology changes within days |
| Sleep metrics | 14 | 9.7 | Weekly patterns are stable; seasonal drift over ~2 weeks |
| Blood pressure | 30 | 20.8 | Responds to meds/lifestyle in 2–4 weeks |
| Metabolic labs (glucose, A1c, lipids) | 180 | 124.7 | A1c reflects ~90-day average; lipids are stable absent intervention |
| Renal markers (eGFR, creatinine) | 180 | 124.7 | Chronic kidney trajectory is slow-moving |
| Inflammatory markers (hsCRP, ESR) | 90 | 62.4 | Reactive in acute illness but baseline is relatively stable |
| CBC / hematology | 120 | 83.2 | Moderate turnover; anemia develops over months |
| Thyroid (TSH, T4) | 180 | 124.7 | Slow-moving endocrine axis |
| Nutritional (Vit D, B12, folate) | 180 | 124.7 | Fat-soluble vitamins have long half-lives in tissue |
| Diagnoses / medication changes | ∞ (never decays) | ∞ | Binary facts — a diagnosis is forever until explicitly resolved |
Time Alignment Visualization
At month 10 (between measurements at month 6 and month 14), the system needs an LDL value. The most recent measurement is 148 at month 6.
Carried value: $x_{\text{carried}}^{\text{LDL}}(10) = 148$ (unchanged)
$$c_{\text{LDL}}(10, 6) = \exp\!\left(-\frac{120}{180}\right) = \exp(-0.667) \approx 0.513$$The system carries forward 148 mg/dL with 51.3% confidence. Once a new measurement arrives at month 14 (155), confidence resets to 1.0.
3 Patient Feature Summarization + Fuzzy C-Means Clustering
FCM does NOT receive the raw weekly state vectors. Weekly states are variable-length time series — FCM requires a fixed-length vector per patient. We first summarize each patient's weekly history into a fixed-length feature vector (~80 dimensions), then cluster those summaries.
The raw weekly state vectors are used directly by Lagged Cross-Correlation (Section 4). FCM needs a snapshot of where the patient is, how they've trended, and how volatile they are.
Step 3a — Summarize Weekly States into Patient Feature Vectors
| Feature | Description | Example (Sarah's LDL) |
|---|---|---|
current_state_m | Most recent week's state | +1 (above) |
mean_state_m | Mean state over last 12 weeks | +0.9 |
trend_m | Slope of states (improving/stable/worsening) | 0.0 (stable high) |
volatility_m | Std dev of states | 0.1 |
frac_above_m | Fraction of weeks in above-normal state | 0.95 |
frac_below_m | Fraction of weeks in below-normal state | 0.0 |
longest_streak_m | Longest consecutive weeks in abnormal state | 12 |
Step 3b — Fuzzy C-Means on Summary Vectors
Unlike hard clustering (K-means), Fuzzy C-Means (FCM) assigns each patient a continuous membership vector across all clusters. A patient can be 72% Metabolic-Driven and 15% Inflammation-Linked simultaneously. This matches clinical reality: multi-morbidity is the norm, not the exception.
Objective Function
$$J(U, C) = \sum_{i=1}^{N}\sum_{k=1}^{K} (u_{ik})^p \cdot \|x_i - c_k\|^2$$Update Rule 1: Centroids
$$c_k = \frac{\sum_{i=1}^{N} (u_{ik})^p \cdot x_i}{\sum_{i=1}^{N} (u_{ik})^p}$$Update Rule 2: Memberships
$$u_{ik} = \frac{1}{\displaystyle\sum_{j=1}^{K}\left(\frac{\|x_i - c_k\|}{\|x_i - c_j\|}\right)^{2/(p-1)}}$$Optimal $K$ Selection
$$K^* = \arg\max_K \Big[\text{Silhouette}(K) - \alpha \cdot \text{XieBeni}(K)\Big]$$Cluster Feature Space
Discovered Health Pattern Taxonomy ($K^* = 12$)
Worked Example — Patient Membership Vectors
4 System Correlations (Lagged Cross-Correlation Graph)
Lagged cross-correlation measures the linear association between the current state of system $X$ and the future state of system $Y$, computed at actual measurement timepoints. Unlike standard correlation, the lag structure makes this measure directed — $r_{XY}(\text{lag}) \neq r_{YX}(\text{lag})$ — so we can determine which system predicts which.
Lagged Cross-Correlation at Measurement Points
$$r_{XY}(\text{lag}) = \text{Corr}\!\big(X(t),\; Y(t + \text{lag})\big)$$Directed Edge Retention
A directed edge $X \to Y$ is retained if: (1) $r_{XY}(\text{lag}=1)$ is significant at $p < 0.01$; (2) $|r_{XY}| > |r_{YX}|$; (3) Edge weight $= |r_{XY}(\text{lag}=1)|$.
System Correlation Graph
5 Outcome Prediction (XGBoost + Cox PH)
Feature Vector
$$\varphi_i = \Big[\underbrace{s_t^1, \ldots, s_t^M}_{\text{current states}},\; \underbrace{\Delta_t^{1m}, \Delta_t^{3m}, \Delta_t^{12m}}_{\text{trajectory deltas}},\; \underbrace{u_{i1}, \ldots, u_{iK}}_{\text{cluster memberships}},\; \underbrace{\text{age, sex, BMI, \ldots}}_{\text{demographics}},\; \underbrace{dx_1, \ldots, dx_D}_{\text{comorbidities}}\Big]$$XGBoost Classifier
$$\hat{y}_i = f_{\text{XGB}}(\varphi_i; \hat{\theta}) \qquad \hat{p}_i = \text{isotonic}(\hat{y}_i)$$Cox Proportional Hazards
$$\lambda(t \mid \varphi) = \lambda_0(t) \cdot \exp\!\left(\beta^T \varphi\right)$$Model Calibration
Note on the numbers in these charts: The 0.81 AUC and the curve shapes shown below are illustrative targets, not actual results — we don't have Mayo data access yet. The charts show what these plots will look like when we have real results.
Calibration Plot (Cardiometabolic Deterioration Composite)
ROC Curve — Cardiometabolic Deterioration (AUC = 0.81)
Feature Importance (SHAP Values — Sarah Chen)
6 Calibration & Validation Metrics
| Outcome | Target AUC | Calibration (Brier) | Notes |
|---|---|---|---|
| Cluster transition (Healthy → disease) | ≥ 0.78 | ≤ 0.15 | Requires sufficient Stable-Healthy patients with 12-month follow-up |
| New chronic diagnosis onset | ≥ 0.75 | ≤ 0.12 | Lower prevalence event; Cox PH primary model |
| Cardiometabolic deterioration composite | ≥ 0.80 | ≤ 0.18 | Composite outcome boosts sample size; XGBoost primary |
| PhenoAge acceleration (≥2 yr / 12 mo) | ≥ 0.76 | ≤ 0.14 | Requires all 9 Levine labs at both timepoints |
- Temporal split: Train on data before cutoff date, test on data after. No future leakage.
- 5-fold cross-validation within training set for hyperparameter tuning.
- Isotonic calibration on a held-out calibration fold (separate from test set).
- Subgroup fairness: AUC and calibration reported stratified by age band, sex, and race/ethnicity. Maximum AUC disparity across subgroups ≤ 0.05.
- Confidence intervals: 1,000-iteration bootstrap on test set for all metrics.
7 Five Patient Profiles
Demographics
State Trajectory (5-Week Window)
| Metric | Wk 1 | Wk 2 | Wk 3 | Wk 4 | Wk 5 | Trend |
|---|---|---|---|---|---|---|
| LDL (mg/dL) | 148 | 148 | 150 | 150 | 150 | Stable-high |
| HbA1c (%) | 6.1 | 6.1 | 6.3 | 6.3 | 6.3 | Rising |
| hsCRP (mg/L) | 1.2 | 1.4 | 1.5 | 1.6 | 1.5 | Slightly rising |
| Vit D (ng/mL) | 16 | 16 | 16 | 16 | 16 | Stable-low |
| Sleep (hrs) | 7.2 | 7.0 | 7.1 | 7.3 | 7.1 | Stable-normal |
Health Pattern Membership
Risk Scores (12-month horizon)
State Trajectory (5-Week Window)
| Metric | Wk 1 | Wk 2 | Wk 3 | Wk 4 | Wk 5 | Trend |
|---|---|---|---|---|---|---|
| Sleep Duration (hrs) | 7.4 | 7.3 | 7.1 | 7.2 | 6.8 | Declining |
| HRV (ms) | 61 | 60 | 56 | 59 | 55 | Declining |
| hsCRP (mg/L) | 2.2 | 2.4 | 2.6 | 2.7 | 2.8 | Rising toward threshold |
| NLR | 2.5 | 2.7 | 2.9 | 3.0 | 3.1 | Rising, crossed threshold |
Health Pattern Membership
Risk Scores (12-month horizon)
State Trajectory (5-Week Window)
| Metric | Wk 1 | Wk 2 | Wk 3 | Wk 4 | Wk 5 | Trend |
|---|---|---|---|---|---|---|
| LDL (mg/dL) | 105 | 104 | 105 | 106 | 105 | Stable-normal |
| HbA1c (%) | 5.2 | 5.2 | 5.2 | 5.2 | 5.2 | Stable-normal |
| HRV (ms) | 72 | 74 | 71 | 73 | 72 | Stable-good |
| BP (mmHg) | 118/74 | 116/72 | 120/76 | 118/74 | 118/74 | Optimal |
Health Pattern Membership
Risk Scores (12-month horizon)
8 Data We Need From Mayo
Core Data (Standard EHR)
| Category | Specific Data | Why We Need It |
|---|---|---|
| Lab Results | Lipid panel (LDL, HDL, TG, ApoB, Lp(a)), HbA1c, fasting glucose, insulin, CMP, CBC w/diff, hsCRP, ferritin, ESR, vitamin D, B12, folate, iron, albumin, TSH | State encoding inputs, phenotype features, outcome definitions, PhenoAge computation |
| Vitals (Flowsheet) | HR, BP, weight, BMI, SpO2, walk time, grip strength | Time-alignment pipeline, system correlation inputs |
| Diagnoses | ICD-10 codes with onset dates | Cohort inclusion, comorbidity features, outcome event definitions |
| Medications | Drug name, class, start/stop dates, dose | Treatment-response features, phenotype context |
| Demographics | Age, sex, race/ethnicity | Demographic stratification, fairness audits |
| Encounters | Visit type, date, provider specialty | Longitudinal density, time-alignment anchor points |
| Social History | Smoking, alcohol, exercise, sleep self-report | Lifestyle features for phenotype discovery |
- Inflammaging: IL-6, CRP, sTNFR-II
- GDF-15 (strongest single mortality predictor in St. Sauver 2023)
- IGF-1 + fasting insulin (nutrient-signaling / longevity axis)
- VO2 max (cardiorespiratory fitness) and grip strength
- Cystatin-C and NT-proBNP (cardiovascular aging)
9 End-to-End Pipeline
The exported models become tools the personal health AI companion calls at runtime. Cluster centroids and reference distributions become RAG context. The system-correlation graph provides evidence-backed explanations. The companion itself is never fine-tuned on Mayo data — it gets smarter by operating over Mayo-validated tools and knowledge.
10 What Mayo Data Enables
| Capability | Before Mayo | After Mayo |
|---|---|---|
| Cluster discovery | 12 hypothesized phenotypes | Data-driven $K^*$ with validated centroids |
| System correlation graph | 6 edges based on literature | Statistically significant directed graph ($p < 0.01$, $n = 2.5$M) |
| Outcome prediction | Rule-based heuristic | XGBoost + Cox PH with AUC > 0.80 and isotonic calibration |
| Confidence decay | Literature-based $\tau_m$ | Empirically calibrated half-lives per metric per population |
| Statistical power | Cannot detect rare patterns | 0.5% support = 12,500 patients; detects small effects |
Timeline
| Phase | Weeks | Deliverable |
|---|---|---|
| 1. Cohort assembly & feature extraction | 1-6 | Cleaned, state-encoded, time-aligned dataset; ~80-dim summary vectors |
| 2. Pattern discovery | 5-11 | Validated $K^*$, FCM centroids, lagged cross-correlation graph |
| 3. Outcome modeling & calibration | 9-16 | Calibrated XGBoost + Cox PH for 4 outcome endpoints, fairness audit |
| 4. Validation & export | 15-20 | Validation report; export package; integration into Healthena tooling |
20 weeks of data access, from cohort assembly to an approved, validated export package.
11 AI Infrastructure Compliance
We do not bring in GPT-4o, Gemini, BERT, or any LLM. Our methodology is entirely non-generative by design. Our personal health AI companion stays on Healthena's own infrastructure and is never modified by Mayo data.
| Export | Mayo Category | Compliance Basis |
|---|---|---|
| Trained XGBoost / LightGBM models (JSON) | Traditional model export | Tree-based, no embeddings, no gradients of source data |
| Trained Cox PH models | Traditional model export | Classical statistical model, interpretable coefficients |
| FCM cluster centroids | Traditional model + aggregated stats | Centroids are aggregates over many patients; no individual data |
| System-correlation graph | Aggregated statistics | Population-level graph, not per-patient |
| Validation report (AUC, Brier, calibration, fairness) | Aggregated statistics | Cohort-level metrics with CIs |
| Source code | Source code | Reviewed for any embedded patient data — none |
| Item | Reason |
|---|---|
| Any row-level or patient-level data | Mayo policy prohibits |
| Embeddings, vectors, or gradients of source data | Restricted under Mayo's embedding export rule |
| Fine-tuned generative models | Not allowed; also not applicable to our methodology |
| Any artifact with <10 patients per aggregated cell | Mayo policy minimum |
12 References
St. Sauver et al. (2023). Biomarkers of cellular senescence and risk of death in humans. Aging Cell, 22, e14006.
Levine et al. (2018). An epigenetic biomarker of aging for lifespan and healthspan. Aging, 10(4), 573–591.
Bezdek, J. C. (1981). Pattern Recognition with Fuzzy Objective Function Algorithms. Plenum Press.
Chen & Guestrin (2016). XGBoost: A scalable tree boosting system. KDD 2016, 785–794.
Lundberg & Lee (2017). A unified approach to interpreting model predictions. NeurIPS, 30, 4765–4774.
Cox, D. R. (1972). Regression models and life-tables. J. Royal Statistical Society: Series B, 34(2), 187–202.
Collins et al. (2015). TRIPOD statement. BMJ, 350, g7594.
Several specific implementation choices (modality-specific confidence half-lives, K-selection trade-off parameter α, etc.) are starting values to be refined empirically against Mayo's cohort during the program. The references above ground the methodology; the parameters will be fit from data and reported in the final validation package.